Systems and methods for GSLB auto synchronization

ABSTRACT

Centralized system for synchronizing a Global Server Load Balancing (GSLB) site hierarchy across a plurality of appliances in a multi-site deployment. With synchronization, differences in configurations across appliances may be determined and changes to configurations may automatically be distributed and applied on each appliance at each site to operate all the sites with a common single GSLB site hierarchy configuration. This reduces the challenging in configuration maintenance for the multi-site deployment.

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the file or records of thePatent and Trademark Office, but otherwise reserves all copyright rightswhatsoever.

FIELD OF THE INVENTION

The present application generally relates to data communicationnetworks. In particular, the present application relates to systems andmethods for automatically synchronizing global server load balancingconfiguration among a plurality of site appliances.

BACKGROUND OF THE INVENTION

An application delivery controller may act as an intermediary betweenclients and servers. The application delivery controller may havemultiple features for controlling or managing network traffic betweenthe clients and servers. These features may be configured by anadministrators. As the number of supported features of the applicationdelivery controller grow, the administrator performs or is responsiblefor more configuration. As the application delivery controller isdeployed in more, larger and different environments, the use of theapplication delivery controller becomes more complex as well as itsconfiguration. In many enterprise infrastructures, multiple controllersmay be deployed to handle different functionality. Each of thesecontrollers may have a different configuration for which theadministration maintains. An administrator of these application deliverycontroller may be challenged in configuring or maintaining aconfiguration of these controllers in any one or more environments.

BRIEF SUMMARY OF THE INVENTION

The present solution provides centralized systems and methods forsynchronizing a Global Server Load Balancing (GSLB) site hierarchyacross a plurality of appliances in a multi-site deployment. Withsynchronization, differences in configurations across appliances may bedetermined and changes to configurations may automatically bedistributed and applied on each appliance at each site to operate allthe sites with a common single GSLB site hierarchy configuration. Thisreduces the challenging in configuration maintenance for the multi-sitedeployment.

In one aspect, the present invention is related to a method forsynchronizing configurations between a plurality of global server loadbalancing (GSLB) appliances. The method includes identifying, by a user,a first appliance as a master GSLB node. The first appliance and one ormore appliances are identified to provide GSLB services. The firstappliance obtains a GSLB configuration from each of the one or moreappliances and compares the GSLB configuration obtained from each of theone or more appliances to a first GSLB configuration executing on thefirst appliance The first appliance generates a configuration commandset for each of the one or more appliances based on the comparison. Eachof the configuration command sets comprising one or more commands tosynchronize the GSLB configuration with the first GSLB configuration ofthe first appliance. The method also includes applying by the firstappliance each of the configuration command sets to a correspondingappliance of the one or more appliances.

In some embodiments, the method includes a step of configuring the firstappliance to auto-login to each of the one or more appliances. In oneembodiment, the first appliances determines the one or more appliancesidentified by the first GSLB configuration. In another embodiments, themethod includes the step of automatically performing a login to each ofthe one or more appliances. The first appliance may execute a command oneach of the one or more appliances to output a currently executing GSLBconfiguration. In some embodiments, the first appliance determines oneor more differences between the first GSLB configuration and the GSLBconfiguration of each of the one or more appliances.

In some embodiments, the first appliance generates based on thecomparison a first configuration command set for synchronizing thesecond currently executing GSLB configuration of a second appliance withthe first GSLB configuration and a second configuration set forsynchronizing the third currently executing GSLB configuration of thethird appliance with the first GSLB configuration. In some embodiments,the method also includes obtaining information that a second applianceof the one or more appliances is not to be synchronized. The firstappliance executes on each of the one or more appliances a remotecommand to apply the GSLB configuration set corresponding to each of theone or more appliances. Responsive to applying the configuration commandset, each of the one or more appliances executing a GSLB configurationcorresponding to the first GSLB configuration.

In some aspects, the present invention is related to a system forsynchronizing configurations between a plurality of global server loadbalancing (GSLB) appliances. The system includes a first applianceidentified as a master GSLB node. The first appliance and one or moreappliances identified to provide GSLB services. An interface of thefirst appliance obtains a GSLB configuration from each of the one ormore appliances. A comparator of first appliance compares the GSLBconfiguration obtained from each of the one or more appliances to afirst GSLB configuration executing on the first appliance. A generatorof the first appliance generates a configuration command set for each ofthe one or more appliances based on the comparison. Each of theconfiguration command sets includes one or more commands to synchronizethe GSLB configuration with the first GSLB configuration of theappliance. The first appliance applies each of the configuration commandsets to a corresponding appliance of the one or more appliances.

In some embodiments, the first appliance is configured to auto-login toeach of the one or more appliances. In another embodiment, the firstappliance determines the one or more appliances identified by the firstGSLB configuration. In some embodiments, the interface automaticallyperforms a login to each of the one or more appliances. In someembodiments, the interface executes a command on each of the one or moreappliances to output a currently executing GSLB configuration. Inanother embodiment, the comparator determines one or more differencesbetween the first GSLB configuration and the GSLB configuration of eachof the one or more appliances.

In some embodiments, the generator based on the comparison generates afirst configuration command set for synchronizing the second currentlyexecuting GSLB configuration of a second appliance with the first GSLBconfiguration and a second configuration set for synchronizing the thirdcurrently executing GSLB configuration of the third appliance with thefirst GSLB configuration. In another embodiment, the interface obtainsinformation that a second appliance of the one or more appliances is notbe synchronized and the appliance does perform synchronization of thesecond appliance.

In many embodiments, the interface executes on each of the one or moreappliances a remote command to apply the GSLB configuration setcorresponding to each of the one or more appliances. In someembodiments, each of the one or more appliances executes responsive toapplying the configuration command set a GSLB configurationcorresponding to the first GSLB configuration.

The details of various embodiments of the invention are set forth in theaccompanying drawings and the description below.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other objects, aspects, features, and advantages ofthe invention will become more apparent and better understood byreferring to the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1A is a block diagram of an embodiment of a network environment fora client to access a server via an appliance;

FIG. 1B is a block diagram of an embodiment of an environment fordelivering a computing environment from a server to a client via anappliance;

FIG. 1C is a block diagram of another embodiment of an environment fordelivering a computing environment from a server to a client via aplurality of appliances;

FIG. 1D is a block diagram of another embodiment of an environment fordelivering a computing environment from a server to a client via;

FIGS. 1E and 1F are block diagrams of embodiments of a computing device;

FIG. 2A is a block diagram of an embodiment of an appliance forprocessing communications between a client and a server;

FIG. 2B is a block diagram of another embodiment of an appliance foroptimizing, accelerating, load-balancing and routing communicationsbetween a client and a server;

FIG. 3 is a block diagram of an embodiment of a client for communicatingwith a server via the appliance;

FIG. 4A is a block diagram of an embodiment of an environment of amulti-site deployment of appliances;

FIG. 4B is a block diagram of an embodiment of an appliance supportingbatchable and hierarchical configuration for a multi-site deployment;

FIG. 4C is a block diagram of an embodiment of another embodiment ofconfigurations and communications in one embodiment of a multi-sitedeployment;

FIG. 4D is a block diagram of an embodiment of an embodiment ofconfigurations and communications in an embodiment of a multi-sitedeployment using the batchable and hierarchical configuration;

FIG. 4E is a flow diagram of an embodiment of steps of a method forconfiguring appliances of a multi-site deployment via a batchable andhierarchical configuration;

FIG. 5A is a block diagram of an embodiment of an appliance forsynchronizing configurations among appliances; and

FIG. 5B is a flow diagram of an embodiment of steps of a method forsynchronizing configurations among appliances.

The features and advantages of the present invention will become moreapparent from the detailed description set forth below when taken inconjunction with the drawings, in which like reference charactersidentify corresponding elements throughout. In the drawings, likereference numbers generally indicate identical, functionally similar,and/or structurally similar elements.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of reading the description of the various embodimentsbelow, the following descriptions of the sections of the specificationand their respective contents may be helpful:

-   -   Section A describes a network environment and computing        environment which may be useful for practicing embodiments        described herein;    -   Section B describes embodiments of systems and methods for        delivering a computing environment to a remote user;    -   Section C describes embodiments of systems and methods for        accelerating communications between a client and a server;    -   Section D describes systems and method of providing a Global        Server Load Balancing (GSLB) batchable and hierarchical        configuration among a plurality of sites;    -   Section E describes systems and method of providing automatic        synchronization of Global Server Load Balancing (GSLB)        configuration among a plurality of appliances.        A. Network and Computing Environment

Prior to discussing the specifics of embodiments of the systems andmethods of an appliance and/or client, it may be helpful to discuss thenetwork and computing environments in which such embodiments may bedeployed. Referring now to FIG. 1A, an embodiment of a networkenvironment is depicted. In brief overview, the network environmentcomprises one or more clients 102 a-102 n (also generally referred to aslocal machine(s) 102, or client(s) 102) in communication with one ormore servers 106 a-106 n (also generally referred to as server(s) 106,or remote machine(s) 106) via one or more networks 104, 104′ (generallyreferred to as network 104). In some embodiments, a client 102communicates with a server 106 via an appliance 200.

Although FIG. 1A shows a network 104 and a network 104′ between theclients 102 and the servers 106, the clients 102 and the servers 106 maybe on the same network 104. The networks 104 and 104′ can be the sametype of network or different types of networks. The network 104 and/orthe network 104′ can be a local-area network (LAN), such as a companyIntranet, a metropolitan area network (MAN), or a wide area network(WAN), such as the Internet or the World Wide Web. In one embodiment,network 104′ may be a private network and network 104 may be a publicnetwork. In some embodiments, network 104 may be a private network andnetwork 104′ a public network. In another embodiment, networks 104 and104′ may both be private networks. In some embodiments, clients 102 maybe located at a branch office of a corporate enterprise communicatingvia a WAN connection over the network 104 to the servers 106 located ata corporate data center.

The network 104 and/or 104′ be any type and/or form of network and mayinclude any of the following: a point to point network, a broadcastnetwork, a wide area network, a local area network, a telecommunicationsnetwork, a data communication network, a computer network, an ATM(Asynchronous Transfer Mode) network, a SONET (Synchronous OpticalNetwork) network, a SDH (Synchronous Digital Hierarchy) network, awireless network and a wireline network. In some embodiments, thenetwork 104 may comprise a wireless link, such as an infrared channel orsatellite band. The topology of the network 104 and/or 104′ may be abus, star, or ring network topology. The network 104 and/or 104′ andnetwork topology may be of any such network or network topology as knownto those ordinarily skilled in the art capable of supporting theoperations described herein.

As shown in FIG. 1A, the appliance 200, which also may be referred to asan interface unit 200 or gateway 200, is shown between the networks 104and 104′. In some embodiments, the appliance 200 may be located onnetwork 104. For example, a branch office of a corporate enterprise maydeploy an appliance 200 at the branch office. In other embodiments, theappliance 200 may be located on network 104′. For example, an appliance200 may be located at a corporate data center. In yet anotherembodiment, a plurality of appliances 200 may be deployed on network104. In some embodiments, a plurality of appliances 200 may be deployedon network 104′. In one embodiment, a first appliance 200 communicateswith a second appliance 200′. In other embodiments, the appliance 200could be a part of any client 102 or server 106 on the same or differentnetwork 104,104′ as the client 102. One or more appliances 200 may belocated at any point in the network or network communications pathbetween a client 102 and a server 106.

In some embodiments, the appliance 200 comprises any of the networkdevices manufactured by Citrix Systems, Inc. of Ft. Lauderdale Fla.,referred to as Citrix NetScaler devices. In other embodiments, theappliance 200 includes any of the product embodiments referred to asWebAccelerator and BigIP manufactured by F5 Networks, Inc. of Seattle,Wash. In another embodiment, the appliance 205 includes any of the DXacceleration device platforms and/or the SSL VPN series of devices, suchas SA 700, SA 2000, SA 4000, and SA 6000 devices manufactured by JuniperNetworks, Inc. of Sunnyvale, Calif. In yet another embodiment, theappliance 200 includes any application acceleration and/or securityrelated appliances and/or software manufactured by Cisco Systems, Inc.of San Jose, Calif., such as the Cisco ACE Application Control EngineModule service software and network modules, and Cisco AVS SeriesApplication Velocity System.

In one embodiment, the system may include multiple, logically-groupedservers 106. In these embodiments, the logical group of servers may bereferred to as a server farm 38. In some of these embodiments, theserves 106 may be geographically dispersed. In some cases, a farm 38 maybe administered as a single entity. In other embodiments, the serverfarm 38 comprises a plurality of server farms 38. In one embodiment, theserver farm executes one or more applications on behalf of one or moreclients 102.

The servers 106 within each farm 38 can be heterogeneous. One or more ofthe servers 106 can operate according to one type of operating systemplatform (e.g., WINDOWS NT, manufactured by Microsoft Corp. of Redmond,Wash.), while one or more of the other servers 106 can operate onaccording to another type of operating system platform (e.g., Unix orLinux). The servers 106 of each farm 38 do not need to be physicallyproximate to another server 106 in the same farm 38. Thus, the group ofservers 106 logically grouped as a farm 38 may be interconnected using awide-area network (WAN) connection or medium-area network (MAN)connection. For example, a farm 38 may include servers 106 physicallylocated in different continents or different regions of a continent,country, state, city, campus, or room. Data transmission speeds betweenservers 106 in the farm 38 can be increased if the servers 106 areconnected using a local-area network (LAN) connection or some form ofdirect connection.

Servers 106 may be referred to as a file server, application server, webserver, proxy server, or gateway server. In some embodiments, a server106 may have the capacity to function as either an application server oras a master application server. In one embodiment, a server 106 mayinclude an Active Directory. The clients 102 may also be referred to asclient nodes or endpoints. In some embodiments, a client 102 has thecapacity to function as both a client node seeking access toapplications on a server and as an application server providing accessto hosted applications for other clients 102 a-102 n.

In some embodiments, a client 102 communicates with a server 106. In oneembodiment, the client 102 communicates directly with one of the servers106 in a farm 38. In another embodiment, the client 102 executes aprogram neighborhood application to communicate with a server 106 in afarm 38. In still another embodiment, the server 106 provides thefunctionality of a master node. In some embodiments, the client 102communicates with the server 106 in the farm 38 through a network 104.Over the network 104, the client 102 can, for example, request executionof various applications hosted by the servers 106 a-106 n in the farm 38and receive output of the results of the application execution fordisplay. In some embodiments, only the master node provides thefunctionality required to identify and provide address informationassociated with a server 106′ hosting a requested application.

In one embodiment, the server 106 provides functionality of a webserver. In another embodiment, the server 106 a receives requests fromthe client 102, forwards the requests to a second server 106 b andresponds to the request by the client 102 with a response to the requestfrom the server 106 b. In still another embodiment, the server 106acquires an enumeration of applications available to the client 102 andaddress information associated with a server 106 hosting an applicationidentified by the enumeration of applications. In yet anotherembodiment, the server 106 presents the response to the request to theclient 102 using a web interface. In one embodiment, the client 102communicates directly with the server 106 to access the identifiedapplication. In another embodiment, the client 102 receives applicationoutput data, such as display data, generated by an execution of theidentified application on the server 106.

Referring now to FIG. 1B, an embodiment of a network environmentdeploying multiple appliances 200 is depicted. A first appliance 200 maybe deployed on a first network 104 and a second appliance 200′ on asecond network 104′. For example a corporate enterprise may deploy afirst appliance 200 at a branch office and a second appliance 200′ at adata center. In another embodiment, the first appliance 200 and secondappliance 200′ are deployed on the same network 104 or network 104. Forexample, a first appliance 200 may be deployed for a first server farm38, and a second appliance 200 may be deployed for a second server farm38′. In another example, a first appliance 200 may be deployed at afirst branch office while the second appliance 200′ is deployed at asecond branch office. In some embodiments, the first appliance 200 andsecond appliance 200′ work in cooperation or in conjunction with eachother to accelerate network traffic or the delivery of application anddata between a client and a server

Referring now to FIG. 1C, another embodiment of a network environmentdeploying the appliance 200 with one or more other types of appliances,such as between one or more WAN optimization appliance 205, 205′ isdepicted. For example a first WAN optimization appliance 205 is shownbetween networks 104 and 104′ and s second WAN optimization appliance205′ may be deployed between the appliance 200 and one or more servers106. By way of example, a corporate enterprise may deploy a first WANoptimization appliance 205 at a branch office and a second WANoptimization appliance 205′ at a data center. In some embodiments, theappliance 205 may be located on network 104′. In other embodiments, theappliance 205′ may be located on network 104. In some embodiments, theappliance 205′ may be located on network 104′ or network 104″. In oneembodiment, the appliance 205 and 205′ are on the same network. Inanother embodiment, the appliance 205 and 205′ are on differentnetworks. In another example, a first WAN optimization appliance 205 maybe deployed for a first server farm 38 and a second WAN optimizationappliance 205′ for a second server farm 38′

In one embodiment, the appliance 205 is a device for accelerating,optimizing or otherwise improving the performance, operation, or qualityof service of any type and form of network traffic, such as traffic toand/or from a WAN connection. In some embodiments, the appliance 205 isa performance enhancing proxy. In other embodiments, the appliance 205is any type and form of WAN optimization or acceleration device,sometimes also referred to as a WAN optimization controller. In oneembodiment, the appliance 205 is any of the product embodiments referredto as WANScaler manufactured by Citrix Systems, Inc. of Ft. Lauderdale,Fla. In other embodiments, the appliance 205 includes any of the productembodiments referred to as BIG-IP link controller and WANjetmanufactured by F5 Networks, Inc. of Seattle, Wash. In anotherembodiment, the appliance 205 includes any of the WX and WXC WANacceleration device platforms manufactured by Juniper Networks, Inc. ofSunnyvale, Calif. In some embodiments, the appliance 205 includes any ofthe steelhead line of WAN optimization appliances manufactured byRiverbed Technology of San Francisco, Calif. In other embodiments, theappliance 205 includes any of the WAN related devices manufactured byExpand Networks Inc. of Roseland, N.J. In one embodiment, the appliance205 includes any of the WAN related appliances manufactured by PacketeerInc. of Cupertino, Calif., such as the PacketShaper, iShared, and SkyXproduct embodiments provided by Packeteer. In yet another embodiment,the appliance 205 includes any WAN related appliances and/or softwaremanufactured by Cisco Systems, Inc. of San Jose, Calif., such as theCisco Wide Area Network Application Services software and networkmodules, and Wide Area Network engine appliances.

In one embodiment, the appliance 205 provides application and dataacceleration services for branch-office or remote offices. In oneembodiment, the appliance 205 includes optimization of Wide Area FileServices (WAFS). In another embodiment, the appliance 205 acceleratesthe delivery of files, such as via the Common Internet File System(CIFS) protocol. In other embodiments, the appliance 205 providescaching in memory and/or storage to accelerate delivery of applicationsand data. In one embodiment, the appliance 205 provides compression ofnetwork traffic at any level of the network stack or at any protocol ornetwork layer. In another embodiment, the appliance 205 providestransport layer protocol optimizations, flow control, performanceenhancements or modifications and/or management to accelerate deliveryof applications and data over a WAN connection. For example, in oneembodiment, the appliance 205 provides Transport Control Protocol (TCP)optimizations. In other embodiments, the appliance 205 providesoptimizations, flow control, performance enhancements or modificationsand/or management for any session or application layer protocol.

In another embodiment, the appliance 205 encoded any type and form ofdata or information into custom or standard TCP and/or IP header fieldsor option fields of network packet to announce presence, functionalityor capability to another appliance 205′. In another embodiment, anappliance 205′ may communicate with another appliance 205′ using dataencoded in both TCP and/or IP header fields or options. For example, theappliance may use TCP option(s) or IP header fields or options tocommunicate one or more parameters to be used by the appliances 205,205′ in performing functionality, such as WAN acceleration, or forworking in conjunction with each other.

In some embodiments, the appliance 200 preserves any of the informationencoded in TCP and/or IP header and/or option fields communicatedbetween appliances 205 and 205′. For example, the appliance 200 mayterminate a transport layer connection traversing the appliance 200,such as a transport layer connection from between a client and a servertraversing appliances 205 and 205′. In one embodiment, the appliance 200identifies and preserves any encoded information in a transport layerpacket transmitted by a first appliance 205 via a first transport layerconnection and communicates a transport layer packet with the encodedinformation to a second appliance 205′ via a second transport layerconnection.

Referring now to FIG. 1D, a network environment for delivering and/oroperating a computing environment on a client 102 is depicted. In someembodiments, a server 106 includes an application delivery system 190for delivering a computing environment or an application and/or datafile to one or more clients 102. In brief overview, a client 10 is incommunication with a server 106 via network 104, 104′ and appliance 200.For example, the client 102 may reside in a remote office of a company,e.g., a branch office, and the server 106 may reside at a corporate datacenter. The client 102 comprises a client agent 120, and a computingenvironment 15. The computing environment 15 may execute or operate anapplication that accesses, processes or uses a data file. The computingenvironment 15, application and/or data file may be delivered via theappliance 200 and/or the server 106.

In some embodiments, the appliance 200 accelerates delivery of acomputing environment 15, or any portion thereof, to a client 102. Inone embodiment, the appliance 200 accelerates the delivery of thecomputing environment 15 by the application delivery system 190. Forexample, the embodiments described herein may be used to acceleratedelivery of a streaming application and data file processable by theapplication from a central corporate data center to a remote userlocation, such as a branch office of the company. In another embodiment,the appliance 200 accelerates transport layer traffic between a client102 and a server 106. The appliance 200 may provide accelerationtechniques for accelerating any transport layer payload from a server106 to a client 102, such as: 1) transport layer connection pooling, 2)transport layer connection multiplexing, 3) transport control protocolbuffering, 4) compression and 5) caching. In some embodiments, theappliance 200 provides load balancing of servers 106 in responding torequests from clients 102. In other embodiments, the appliance 200 actsas a proxy or access server to provide access to the one or more servers106. In another embodiment, the appliance 200 provides a secure virtualprivate network connection from a first network 104 of the client 102 tothe second network 104′ of the server 106, such as an SSL VPNconnection. It yet other embodiments, the appliance 200 providesapplication firewall security, control and management of the connectionand communications between a client 102 and a server 106.

In some embodiments, the application delivery management system 190provides application delivery techniques to deliver a computingenvironment to a desktop of a user, remote or otherwise, based on aplurality of execution methods and based on any authentication andauthorization policies applied via a policy engine 195. With thesetechniques, a remote user may obtain a computing environment and accessto server stored applications and data files from any network connecteddevice 100. In one embodiment, the application delivery system 190 mayreside or execute on a server 106. In another embodiment, theapplication delivery system 190 may reside or execute on a plurality ofservers 106 a-106 n. In some embodiments, the application deliverysystem 190 may execute in a server farm 38. In one embodiment, theserver 106 executing the application delivery system 190 may also storeor provide the application and data file. In another embodiment, a firstset of one or more servers 106 may execute the application deliverysystem 190, and a different server 106 n may store or provide theapplication and data file. In some embodiments, each of the applicationdelivery system 190, the application, and data file may reside or belocated on different servers. In yet another embodiment, any portion ofthe application delivery system 190 may reside, execute or be stored onor distributed to the appliance 200, or a plurality of appliances.

The client 102 may include a computing environment 15 for executing anapplication that uses or processes a data file. The client 102 vianetworks 104, 104′ and appliance 200 may request an application and datafile from the server 106. In one embodiment, the appliance 200 mayforward a request from the client 102 to the server 106. For example,the client 102 may not have the application and data file stored oraccessible locally. In response to the request, the application deliverysystem 190 and/or server 106 may deliver the application and data fileto the client 102. For example, in one embodiment, the server 106 maytransmit the application as an application stream to operate incomputing environment 15 on client 102.

In some embodiments, the application delivery system 190 comprises anyportion of the Citrix Access Suite™ by Citrix Systems, Inc., such as theMetaFrame or Citrix Presentation Server™ and/or any of the Microsoft®Windows Terminal Services manufactured by the Microsoft Corporation. Inone embodiment, the application delivery system 190 may deliver one ormore applications to clients 102 or users via a remote-display protocolor otherwise via remote-based or server-based computing. In anotherembodiment, the application delivery system 190 may deliver one or moreapplications to clients or users via steaming of the application.

In one embodiment, the application delivery system 190 includes a policyengine 195 for controlling and managing the access to, selection ofapplication execution methods and the delivery of applications. In someembodiments, the policy engine 195 determines the one or moreapplications a user or client 102 may access. In another embodiment, thepolicy engine 195 determines how the application should be delivered tothe user or client 102, e.g., the method of execution. In someembodiments, the application delivery system 190 provides a plurality ofdelivery techniques from which to select a method of applicationexecution, such as a server-based computing, streaming or delivering theapplication locally to the client 120 for local execution.

In one embodiment, a client 102 requests execution of an applicationprogram and the application delivery system 190 comprising a server 106selects a method of executing the application program. In someembodiments, the server 106 receives credentials from the client 102. Inanother embodiment, the server 106 receives a request for an enumerationof available applications from the client 102. In one embodiment, inresponse to the request or receipt of credentials, the applicationdelivery system 190 enumerates a plurality of application programsavailable to the client 102. The application delivery system 190receives a request to execute an enumerated application. The applicationdelivery system 190 selects one of a predetermined number of methods forexecuting the enumerated application, for example, responsive to apolicy of a policy engine. The application delivery system 190 mayselect a method of execution of the application enabling the client 102to receive application-output data generated by execution of theapplication program on a server 106. The application delivery system 190may select a method of execution of the application enabling the localmachine 10 to execute the application program locally after retrieving aplurality of application files comprising the application. In yetanother embodiment, the application delivery system 190 may select amethod of execution of the application to stream the application via thenetwork 104 to the client 102.

A client 102 may execute, operate or otherwise provide an application,which can be any type and/or form of software, program, or executableinstructions such as any type and/or form of web browser, web-basedclient, client-server application, a thin-client computing client, anActiveX control, or a Java applet, or any other type and/or form ofexecutable instructions capable of executing on client 102. In someembodiments, the application may be a server-based or a remote-basedapplication executed on behalf of the client 102 on a server 106. In oneembodiments the server 106 may display output to the client 102 usingany thin-client or remote-display protocol, such as the IndependentComputing Architecture (ICA) protocol manufactured by Citrix Systems,Inc. of Ft. Lauderdale, Fla. or the Remote Desktop Protocol (RDP)manufactured by the Microsoft Corporation of Redmond, Wash. Theapplication can use any type of protocol and it can be, for example, anHTTP client, an FTP client, an Oscar client, or a Telnet client. Inother embodiments, the application comprises any type of softwarerelated to VoIP communications, such as a soft IP telephone. In furtherembodiments, the application comprises any application related toreal-time data communications, such as applications for streaming videoand/or audio.

In some embodiments, the server 106 or a server farm 38 may be runningone or more applications, such as an application providing a thin-clientcomputing or remote display presentation application. In one embodiment,the server 106 or server farm 38 executes as an application, any portionof the Citrix Access Suite™ by Citrix Systems, Inc., such as theMetaFrame or Citrix Presentation Server™, and/or any of the Microsoft®Windows Terminal Services manufactured by the Microsoft Corporation. Inone embodiment, the application is an ICA client, developed by CitrixSystems, Inc. of Fort Lauderdale, Fla. In other embodiments, theapplication includes a Remote Desktop (RDP) client, developed byMicrosoft Corporation of Redmond, Wash. Also, the server 106 may run anapplication, which for example, may be an application server providingemail services such as Microsoft Exchange manufactured by the MicrosoftCorporation of Redmond, Wash., a web or Internet server, or a desktopsharing server, or a collaboration server. In some embodiments, any ofthe applications may comprise any type of hosted service or products,such as GoToMeeting™ provided by Citrix Online Division, Inc. of SantaBarbara, Calif., WebEx™ provided by WebEx, Inc. of Santa Clara, Calif.,or Microsoft Office Live Meeting provided by Microsoft Corporation ofRedmond, Wash.

Still referring to FIG. 1D, an embodiment of the network environment mayinclude a monitoring server 106A. The monitoring server 106A may includeany type and form performance monitoring service 198. The performancemonitoring service 198 may include monitoring, measurement and/ormanagement software and/or hardware, including data collection,aggregation, analysis, management and reporting. In one embodiment, theperformance monitoring service 198 includes one or more monitoringagents 197. The monitoring agent 197 includes any software, hardware orcombination thereof for performing monitoring, measurement and datacollection activities on a device, such as a client 102, server 106 oran appliance 200, 205. In some embodiments, the monitoring agent 197includes any type and form of script, such as Visual Basic script, orJavascript. In one embodiment, the monitoring agent 197 executestransparently to any application and/or user of the device. In someembodiments, the monitoring agent 197 is installed and operatedunobtrusively to the application or client. In yet another embodiment,the monitoring agent 197 is installed and operated without anyinstrumentation for the application or device.

In some embodiments, the monitoring agent 197 monitors, measures andcollects data on a predetermined frequency. In other embodiments, themonitoring agent 197 monitors, measures and collects data based upondetection of any type and form of event. For example, the monitoringagent 197 may collect data upon detection of a request for a web page orreceipt of an HTTP response. In another example, the monitoring agent197 may collect data upon detection of any user input events, such as amouse click. The monitoring agent 197 may report or provide anymonitored, measured or collected data to the monitoring service 198. Inone embodiment, the monitoring agent 197 transmits information to themonitoring service 198 according to a schedule or a predeterminedfrequency. In another embodiment, the monitoring agent 197 transmitsinformation to the monitoring service 198 upon detection of an event.

In some embodiments, the monitoring service 198 and/or monitoring agent197 performs monitoring and performance measurement of any networkresource or network infrastructure element, such as a client, server,server farm, appliance 200, appliance 205, or network connection. In oneembodiment, the monitoring service 198 and/or monitoring agent 197performs monitoring and performance measurement of any transport layerconnection, such as a TCP or UDP connection. In another embodiment, themonitoring service 198 and/or monitoring agent 197 monitors and measuresnetwork latency. In yet one embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures bandwidth utilization.

In other embodiments, the monitoring service 198 and/or monitoring agent197 monitors and measures end-user response times. In some embodiments,the monitoring service 198 performs monitoring and performancemeasurement of an application. In another embodiment, the monitoringservice 198 and/or monitoring agent 197 performs monitoring andperformance measurement of any session or connection to the application.In one embodiment, the monitoring service 198 and/or monitoring agent197 monitors and measures performance of a browser. In anotherembodiment, the monitoring service 198 and/or monitoring agent 197monitors and measures performance of HTTP based transactions. In someembodiments, the monitoring service 198 and/or monitoring agent 197monitors and measures performance of a Voice over IP (VoIP) applicationor session. In other embodiments, the monitoring service 198 and/ormonitoring agent 197 monitors and measures performance of a remotedisplay protocol application, such as an ICA client or RDP client. Inyet another embodiment, the monitoring service 198 and/or monitoringagent 197 monitors and measures performance of any type and form ofstreaming media. In still a further embodiment, the monitoring service198 and/or monitoring agent 197 monitors and measures performance of ahosted application or a Software-As-A-Service (SaaS) delivery model.

In some embodiments, the monitoring service 198 and/or monitoring agent197 performs monitoring and performance measurement of one or moretransactions, requests or responses related to application. In otherembodiments, the monitoring service 198 and/or monitoring agent 197monitors and measures any portion of an application layer stack, such asany .NET or J2EE calls. In one embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures database or SQLtransactions. In yet another embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures any method, functionor application programming interface (API) call.

In one embodiment, the monitoring service 198 and/or monitoring agent197 performs monitoring and performance measurement of a delivery ofapplication and/or data from a server to a client via one or moreappliances, such as appliance 200 and/or appliance 205. In someembodiments, the monitoring service 198 and/or monitoring agent 197monitors and measures performance of delivery of a virtualizedapplication. In other embodiments, the monitoring service 198 and/ormonitoring agent 197 monitors and measures performance of delivery of astreaming application. In another embodiment, the monitoring service 198and/or monitoring agent 197 monitors and measures performance ofdelivery of a desktop application to a client and/or the execution ofthe desktop application on the client. In another embodiment, themonitoring service 198 and/or monitoring agent 197 monitors and measuresperformance of a client/server application.

In one embodiment, the monitoring service 198 and/or monitoring agent197 is designed and constructed to provide application performancemanagement for the application delivery system 190. For example, themonitoring service 198 and/or monitoring agent 197 may monitor, measureand manage the performance of the delivery of applications via theCitrix Presentation Server. In this example, the monitoring service 198and/or monitoring agent 197 monitors individual ICA sessions. Themonitoring service 198 and/or monitoring agent 197 may measure the totaland per session system resource usage, as well as application andnetworking performance. The monitoring service 198 and/or monitoringagent 197 may identify the active servers for a given user and/or usersession. In some embodiments, the monitoring service 198 and/ormonitoring agent 197 monitors back-end connections between theapplication delivery system 190 and an application and/or databaseserver. The monitoring service 198 and/or monitoring agent 197 maymeasure network latency, delay and volume per user-session or ICAsession.

In some embodiments, the monitoring service 198 and/or monitoring agent197 measures and monitors memory usage for the application deliverysystem 190, such as total memory usage, per user session and/or perprocess. In other embodiments, the monitoring service 198 and/ormonitoring agent 197 measures and monitors CPU usage the applicationdelivery system 190, such as total CPU usage, per user session and/orper process. In another embodiments, the monitoring service 198 and/ormonitoring agent 197 measures and monitors the time required to log-into an application, a server, or the application delivery system, such asCitrix Presentation Server. In one embodiment, the monitoring service198 and/or monitoring agent 197 measures and monitors the duration auser is logged into an application, a server, or the applicationdelivery system 190. In some embodiments, the monitoring service 198and/or monitoring agent 197 measures and monitors active and inactivesession counts for an application, server or application delivery systemsession. In yet another embodiment, the monitoring service 198 and/ormonitoring agent 197 measures and monitors user session latency.

In yet further embodiments, the monitoring service 198 and/or monitoringagent 197 measures and monitors measures and monitors any type and formof server metrics. In one embodiment, the monitoring service 198 and/ormonitoring agent 197 measures and monitors metrics related to systemmemory, CPU usage, and disk storage. In another embodiment, themonitoring service 198 and/or monitoring agent 197 measures and monitorsmetrics related to page faults, such as page faults per second. In otherembodiments, the monitoring service 198 and/or monitoring agent 197measures and monitors round-trip time metrics. In yet anotherembodiment, the monitoring service 198 and/or monitoring agent 197measures and monitors metrics related to application crashes, errorsand/or hangs.

In some embodiments, the monitoring service 198 and monitoring agent 198includes any of the product embodiments referred to as EdgeSightmanufactured by Citrix Systems, Inc. of Ft. Lauderdale, Fla. In anotherembodiment, the performance monitoring service 198 and/or monitoringagent 198 includes any portion of the product embodiments referred to asthe TrueView product suite manufactured by the Symphoniq Corporation ofPalo Alto, Calif. In one embodiment, the performance monitoring service198 and/or monitoring agent 198 includes any portion of the productembodiments referred to as the TeaLeaf CX product suite manufactured bythe TeaLeaf Technology Inc. of San Francisco, Calif. In otherembodiments, the performance monitoring service 198 and/or monitoringagent 198 includes any portion of the business service managementproducts, such as the BMC Performance Manager and Patrol products,manufactured by BMC Software, Inc. of Houston, Tex.

The client 102, server 106, and appliance 200 may be deployed as and/orexecuted on any type and form of computing device, such as a computer,network device or appliance capable of communicating on any type andform of network and performing the operations described herein. FIGS. 1Eand 1F depict block diagrams of a computing device 100 useful forpracticing an embodiment of the client 102, server 106 or appliance 200.As shown in FIGS. 1E and 1F, each computing device 100 includes acentral processing unit 101, and a main memory unit 122. As shown inFIG. 1E, a computing device 100 may include a visual display device 124,a keyboard 126 and/or a pointing device 127, such as a mouse. Eachcomputing device 100 may also include additional optional elements, suchas one or more input/output devices 130 a-130 b (generally referred tousing reference numeral 130), and a cache memory 140 in communicationwith the central processing unit 101.

The central processing unit 101 is any logic circuitry that responds toand processes instructions fetched from the main memory unit 122. Inmany embodiments, the central processing unit is provided by amicroprocessor unit, such as: those manufactured by Intel Corporation ofMountain View, Calif.; those manufactured by Motorola Corporation ofSchaumburg, Ill.; those manufactured by Transmeta Corporation of SantaClara, Calif.; the RS/6000 processor, those manufactured byInternational Business Machines of White Plains, N.Y.; or thosemanufactured by Advanced Micro Devices of Sunnyvale, Calif. Thecomputing device 100 may be based on any of these processors, or anyother processor capable of operating as described herein.

Main memory unit 122 may be one or more memory chips capable of storingdata and allowing any storage location to be directly accessed by themicroprocessor 101, such as Static random access memory (SRAM), BurstSRAM or SynchBurst SRAM (BSRAM), Dynamic random access memory (DRAM),Fast Page Mode DRAM (FPM DRAM), Enhanced DRAM (EDRAM), Extended DataOutput RAM (EDO RAM), Extended Data Output DRAM (EDO DRAM), BurstExtended Data Output DRAM (BEDO DRAM), Enhanced DRAM (EDRAM),synchronous DRAM (SDRAM), JEDEC SRAM, PC100 SDRAM, Double Data RateSDRAM (DDR SDRAM), Enhanced SDRAM (ESDRAM), SyncLink DRAM (SLDRAM),Direct Rambus DRAM (DRDRAM), or Ferroelectric RAM (FRAM). The mainmemory 122 may be based on any of the above described memory chips, orany other available memory chips capable of operating as describedherein. In the embodiment shown in FIG. 1E, the processor 101communicates with main memory 122 via a system bus 150 (described inmore detail below). FIG. 1E depicts an embodiment of a computing device100 in which the processor communicates directly with main memory 122via a memory port 103. For example, in FIG. 1F the main memory 122 maybe DRDRAM.

FIG. 1F depicts an embodiment in which the main processor 101communicates directly with cache memory 140 via a secondary bus,sometimes referred to as a backside bus. In other embodiments, the mainprocessor 101 communicates with cache memory 140 using the system bus150. Cache memory 140 typically has a faster response time than mainmemory 122 and is typically provided by SRAM, BSRAM, or EDRAM. In theembodiment shown in FIG. 1E, the processor 101 communicates with variousI/O devices 130 via a local system bus 150. Various busses may be usedto connect the central processing unit 101 to any of the I/O devices130, including a VESA VL bus, an ISA bus, an EISA bus, a MicroChannelArchitecture (MCA) bus, a PCI bus, a PCI-X bus, a PCI-Express bus, or aNuBus. For embodiments in which the I/O device is a video display 124,the processor 101 may use an Advanced Graphics Port (AGP) to communicatewith the display 124. FIG. 1F depicts an embodiment of a computer 100 inwhich the main processor 101 communicates directly with I/O device 130via HyperTransport, Rapid I/O, or InfiniBand. FIG. 1F also depicts anembodiment in which local busses and direct communication are mixed: theprocessor 101 communicates with I/O device 130 using a localinterconnect bus while communicating with I/O device 130 directly.

The computing device 100 may support any suitable installation device116, such as a floppy disk drive for receiving floppy disks such as3.5-inch, 5.25-inch disks or ZIP disks, a CD-ROM drive, a CD-R/RW drive,a DVD-ROM drive, tape drives of various formats, USB device, hard-driveor any other device suitable for installing software and programs suchas any client agent 120, or portion thereof. The computing device 100may further comprise a storage device 128, such as one or more hard diskdrives or redundant arrays of independent disks, for storing anoperating system and other related software, and for storing applicationsoftware programs such as any program related to the client agent 120.Optionally, any of the installation devices 116 could also be used asthe storage device 128. Additionally, the operating system and thesoftware can be run from a bootable medium, for example, a bootable CD,such as KNOPPIX®, a bootable CD for GNU/Linux that is available as aGNU/Linux distribution from knoppix.net.

Furthermore, the computing device 100 may include a network interface118 to interface to a Local Area Network (LAN), Wide Area Network (WAN)or the Internet through a variety of connections including, but notlimited to, standard telephone lines, LAN or WAN links (e.g., 802.11,T1, T3, 56 kb, X.25), broadband connections (e.g., ISDN, Frame Relay,ATM), wireless connections, or some combination of any or all of theabove. The network interface 118 may comprise a built-in networkadapter, network interface card, PCMCIA network card, card bus networkadapter, wireless network adapter, USB network adapter, modem or anyother device suitable for interfacing the computing device 100 to anytype of network capable of communication and performing the operationsdescribed herein.

A wide variety of I/O devices 130 a-130 n may be present in thecomputing device 100. Input devices include keyboards, mice, trackpads,trackballs, microphones, and drawing tablets. Output devices includevideo displays, speakers, inkjet printers, laser printers, anddye-sublimation printers. The I/O devices 130 may be controlled by anI/O controller 123 as shown in FIG. 1E. The I/O controller may controlone or more I/O devices such as a keyboard 126 and a pointing device127, e.g., a mouse or optical pen. Furthermore, an I/O device may alsoprovide storage 128 and/or an installation medium 116 for the computingdevice 100. In still other embodiments, the computing device 100 mayprovide USB connections to receive handheld USB storage devices such asthe USB Flash Drive line of devices manufactured by Twintech Industry,Inc. of Los Alamitos, Calif.

In some embodiments, the computing device 100 may comprise or beconnected to multiple display devices 124 a-124 n, which each may be ofthe same or different type and/or form. As such, any of the I/O devices130 a-130 n and/or the I/O controller 123 may comprise any type and/orform of suitable hardware, software, or combination of hardware andsoftware to support, enable or provide for the connection and use ofmultiple display devices 124 a-124 n by the computing device 100. Forexample, the computing device 100 may include any type and/or form ofvideo adapter, video card, driver, and/or library to interface,communicate, connect or otherwise use the display devices 124 a-124 n.In one embodiment, a video adapter may comprise multiple connectors tointerface to multiple display devices 124 a-124 n. In other embodiments,the computing device 100 may include multiple video adapters, with eachvideo adapter connected to one or more of the display devices 124 a-124n. In some embodiments, any portion of the operating system of thecomputing device 100 may be configured for using multiple displays 124a-124 n. In other embodiments, one or more of the display devices 124a-124 n may be provided by one or more other computing devices, such ascomputing devices 100 a and 100 b connected to the computing device 100,for example, via a network. These embodiments may include any type ofsoftware designed and constructed to use another computer's displaydevice as a second display device 124 a for the computing device 100.One ordinarily skilled in the art will recognize and appreciate thevarious ways and embodiments that a computing device 100 may beconfigured to have multiple display devices 124 a-124 n.

In further embodiments, an I/O device 130 may be a bridge 170 betweenthe system bus 150 and an external communication bus, such as a USB bus,an Apple Desktop Bus, an RS-232 serial connection, a SCSI bus, aFireWire bus, a FireWire 800 bus, an Ethernet bus, an AppleTalk bus, aGigabit Ethernet bus, an Asynchronous Transfer Mode bus, a HIPPI bus, aSuper HIPPI bus, a SerialPlus bus, a SCI/LAMP bus, a FibreChannel bus,or a Serial Attached small computer system interface bus.

A computing device 100 of the sort depicted in FIGS. 1E and 1F typicallyoperate under the control of operating systems, which control schedulingof tasks and access to system resources. The computing device 100 can berunning any operating system such as any of the versions of theMicrosoft® Windows operating systems, the different releases of the Unixand Linux operating systems, any version of the Mac OS® for Macintoshcomputers, any embedded operating system, any real-time operatingsystem, any open source operating system, any proprietary operatingsystem, any operating systems for mobile computing devices, or any otheroperating system capable of running on the computing device andperforming the operations described herein. Typical operating systemsinclude: WINDOWS 3.x, WINDOWS 95, WINDOWS 98, WINDOWS 2000, WINDOWS NT3.51, WINDOWS NT 4.0, WINDOWS CE, and WINDOWS XP, all of which aremanufactured by Microsoft Corporation of Redmond, Wash.; MacOS,manufactured by Apple Computer of Cupertino, Calif.; OS/2, manufacturedby International Business Machines of Armonk, N.Y.; and Linux, afreely-available operating system distributed by Caldera Corp. of SaltLake City, Utah, or any type and/or form of a Unix operating system,among others.

In other embodiments, the computing device 100 may have differentprocessors, operating systems, and input devices consistent with thedevice. For example, in one embodiment the computer 100 is a Treo 180,270, 1060, 600 or 650 smart phone manufactured by Palm, Inc. In thisembodiment, the Treo smart phone is operated under the control of thePalmOS operating system and includes a stylus input device as well as afive-way navigator device. Moreover, the computing device 100 can be anyworkstation, desktop computer, laptop or notebook computer, server,handheld computer, mobile telephone, any other computer, or other formof computing or telecommunications device that is capable ofcommunication and that has sufficient processor power and memorycapacity to perform the operations described herein.

B. Appliance Architecture

FIG. 2A illustrates an example embodiment of the appliance 200. Thearchitecture of the appliance 200 in FIG. 2A is provided by way ofillustration only and is not intended to be limiting. As shown in FIG.2, appliance 200 comprises a hardware layer 206 and a software layerdivided into a user space 202 and a kernel space 204.

Hardware layer 206 provides the hardware elements upon which programsand services within kernel space 204 and user space 202 are executed.Hardware layer 206 also provides the structures and elements which allowprograms and services within kernel space 204 and user space 202 tocommunicate data both internally and externally with respect toappliance 200. As shown in FIG. 2, the hardware layer 206 includes aprocessing unit 262 for executing software programs and services, amemory 264 for storing software and data, network ports 266 fortransmitting and receiving data over a network, and an encryptionprocessor 260 for performing functions related to Secure Sockets Layerprocessing of data transmitted and received over the network. In someembodiments, the central processing unit 262 may perform the functionsof the encryption processor 260 in a single processor. Additionally, thehardware layer 206 may comprise multiple processors for each of theprocessing unit 262 and the encryption processor 260. The processor 262may include any of the processors 101 described above in connection withFIGS. 1E and 1F. In some embodiments, the central processing unit 262may perform the functions of the encryption processor 260 in a singleprocessor. Additionally, the hardware layer 206 may comprise multipleprocessors for each of the processing unit 262 and the encryptionprocessor 260. For example, in one embodiment, the appliance 200comprises a first processor 262 and a second processor 262′. In otherembodiments, the processor 262 or 262′ comprises a multi-core processor.

Although the hardware layer 206 of appliance 200 is generallyillustrated with an encryption processor 260, processor 260 may be aprocessor for performing functions related to any encryption protocol,such as the Secure Socket Layer (SSL) or Transport Layer Security (TLS)protocol. In some embodiments, the processor 260 may be a generalpurpose processor (GPP), and in further embodiments, may be haveexecutable instructions for performing processing of any securityrelated protocol.

Although the hardware layer 206 of appliance 200 is illustrated withcertain elements in FIG. 2, the hardware portions or components ofappliance 200 may comprise any type and form of elements, hardware orsoftware, of a computing device, such as the computing device 100illustrated and discussed herein in conjunction with FIGS. 1E and 1F. Insome embodiments, the appliance 200 may comprise a server, gateway,router, switch, bridge or other type of computing or network device, andhave any hardware and/or software elements associated therewith.

The operating system of appliance 200 allocates, manages, or otherwisesegregates the available system memory into kernel space 204 and userspace 204. In example software architecture 200, the operating systemmay be any type and/or form of Unix operating system although theinvention is not so limited. As such, the appliance 200 can be runningany operating system such as any of the versions of the Microsoft®Windows operating systems, the different releases of the Unix and Linuxoperating systems, any version of the Mac OS® for Macintosh computers,any embedded operating system, any network operating system, anyreal-time operating system, any open source operating system, anyproprietary operating system, any operating systems for mobile computingdevices or network devices, or any other operating system capable ofrunning on the appliance 200 and performing the operations describedherein.

The kernel space 204 is reserved for running the kernel 230, includingany device drivers, kernel extensions or other kernel related software.As known to those skilled in the art, the kernel 230 is the core of theoperating system, and provides access, control, and management ofresources and hardware-related elements of the application 104. Inaccordance with an embodiment of the appliance 200, the kernel space 204also includes a number of network services or processes working inconjunction with a cache manager 232, sometimes also referred to as theintegrated cache, the benefits of which are described in detail furtherherein. Additionally, the embodiment of the kernel 230 will depend onthe embodiment of the operating system installed, configured, orotherwise used by the device 200.

In one embodiment, the device 200 comprises one network stack 267, suchas a TCP/IP based stack, for communicating with the client 102 and/orthe server 106. In one embodiment, the network stack 267 is used tocommunicate with a first network, such as network 108, and a secondnetwork 110. In some embodiments, the device 200 terminates a firsttransport layer connection, such as a TCP connection of a client 102,and establishes a second transport layer connection to a server 106 foruse by the client 102, e.g., the second transport layer connection isterminated at the appliance 200 and the server 106. The first and secondtransport layer connections may be established via a single networkstack 267. In other embodiments, the device 200 may comprise multiplenetwork stacks, for example 267 and 267′, and the first transport layerconnection may be established or terminated at one network stack 267,and the second transport layer connection on the second network stack267′. For example, one network stack may be for receiving andtransmitting network packet on a first network, and another networkstack for receiving and transmitting network packets on a secondnetwork. In one embodiment, the network stack 267 comprises a buffer 243for queuing one or more network packets for transmission by theappliance 200.

As shown in FIG. 2, the kernel space 204 includes the cache manager 232,a high-speed layer 2-7 integrated packet engine 240, an encryptionengine 234, a policy engine 236 and multi-protocol compression logic238. Running these components or processes 232, 240, 234, 236 and 238 inkernel space 204 or kernel mode instead of the user space 202 improvesthe performance of each of these components, alone and in combination.Kernel operation means that these components or processes 232, 240, 234,236 and 238 run in the core address space of the operating system of thedevice 200. For example, running the encryption engine 234 in kernelmode improves encryption performance by moving encryption and decryptionoperations to the kernel, thereby reducing the number of transitionsbetween the memory space or a kernel thread in kernel mode and thememory space or a thread in user mode. For example, data obtained inkernel mode may not need to be passed or copied to a process or threadrunning in user mode, such as from a kernel level data structure to auser level data structure. In another aspect, the number of contextswitches between kernel mode and user mode are also reduced.Additionally, synchronization of and communications between any of thecomponents or processes 232, 240, 235, 236 and 238 can be performed moreefficiently in the kernel space 204.

In some embodiments, any portion of the components 232, 240, 234, 236and 238 may run or operate in the kernel space 204, while other portionsof these components 232, 240, 234, 236 and 238 may run or operate inuser space 202. In one embodiment, the appliance 200 uses a kernel-leveldata structure providing access to any portion of one or more networkpackets, for example, a network packet comprising a request from aclient 102 or a response from a server 106. In some embodiments, thekernel-level data structure may be obtained by the packet engine 240 viaa transport layer driver interface or filter to the network stack 267.The kernel-level data structure may comprise any interface and/or dataaccessible via the kernel space 204 related to the network stack 267,network traffic or packets received or transmitted by the network stack267. In other embodiments, the kernel-level data structure may be usedby any of the components or processes 232, 240, 234, 236 and 238 toperform the desired operation of the component or process. In oneembodiment, a component 232, 240, 234, 236 and 238 is running in kernelmode 204 when using the kernel-level data structure, while in anotherembodiment, the component 232, 240, 234, 236 and 238 is running in usermode when using the kernel-level data structure. In some embodiments,the kernel-level data structure may be copied or passed to a secondkernel-level data structure, or any desired user-level data structure.

The cache manager 232 may comprise software, hardware or any combinationof software and hardware to provide cache access, control and managementof any type and form of content, such as objects or dynamicallygenerated objects served by the originating servers 106. The data,objects or content processed and stored by the cache manager 232 maycomprise data in any format, such as a markup language, or communicatedvia any protocol. In some embodiments, the cache manager 232 duplicatesoriginal data stored elsewhere or data previously computed, generated ortransmitted, in which the original data may require longer access timeto fetch, compute or otherwise obtain relative to reading a cache memoryelement. Once the data is stored in the cache memory element, future usecan be made by accessing the cached copy rather than refetching orrecomputing the original data, thereby reducing the access time. In someembodiments, the cache memory element may comprise a data object inmemory 264 of device 200. In other embodiments, the cache memory elementmay comprise memory having a faster access time than memory 264. Inanother embodiment, the cache memory element may comprise any type andform of storage element of the device 200, such as a portion of a harddisk. In some embodiments, the processing unit 262 may provide cachememory for use by the cache manager 232. In yet further embodiments, thecache manager 232 may use any portion and combination of memory,storage, or the processing unit for caching data, objects, and othercontent.

Furthermore, the cache manager 232 includes any logic, functions, rules,or operations to perform any embodiments of the techniques of theappliance 200 described herein. For example, the cache manager 232includes logic or functionality to invalidate objects based on theexpiration of an invalidation time period or upon receipt of aninvalidation command from a client 102 or server 106. In someembodiments, the cache manager 232 may operate as a program, service,process or task executing in the kernel space 204, and in otherembodiments, in the user space 202. In one embodiment, a first portionof the cache manager 232 executes in the user space 202 while a secondportion executes in the kernel space 204. In some embodiments, the cachemanager 232 can comprise any type of general purpose processor (GPP), orany other type of integrated circuit, such as a Field Programmable GateArray (FPGA), Programmable Logic Device (PLD), or Application SpecificIntegrated Circuit (ASIC).

The policy engine 236 may include, for example, an intelligentstatistical engine or other programmable application(s). In oneembodiment, the policy engine 236 provides a configuration mechanism toallow a user to identifying, specify, define or configure a cachingpolicy. Policy engine 236, in some embodiments, also has access tomemory to support data structures such as lookup tables or hash tablesto enable user-selected caching policy decisions. In other embodiments,the policy engine 236 may comprise any logic, rules, functions oroperations to determine and provide access, control and management ofobjects, data or content being cached by the appliance 200 in additionto access, control and management of security, network traffic, networkaccess, compression or any other function or operation performed by theappliance 200. Further examples of specific caching policies are furtherdescribed herein.

The encryption engine 234 comprises any logic, business rules, functionsor operations for handling the processing of any security relatedprotocol, such as SSL or TLS, or any function related thereto. Forexample, the encryption engine 234 encrypts and decrypts networkpackets, or any portion thereof, communicated via the appliance 200. Theencryption engine 234 may also setup or establish SSL or TLS connectionson behalf of the client 102 a-102 n, server 106 a-106 n, or appliance200. As such, the encryption engine 234 provides offloading andacceleration of SSL processing. In one embodiment, the encryption engine234 uses a tunneling protocol to provide a virtual private networkbetween a client 102 a-102 n and a server 106 a-106 n. In someembodiments, the encryption engine 234 is in communication with theEncryption processor 260. In other embodiments, the encryption engine234 comprises executable instructions running on the Encryptionprocessor 260.

The multi-protocol compression engine 238 comprises any logic, businessrules, function or operations for compressing one or more protocols of anetwork packet, such as any of the protocols used by the network stack267 of the device 200. In one embodiment, multi-protocol compressionengine 238 compresses bi-directionally between clients 102 a-102 n andservers 106 a-106 n any TCP/IP based protocol, including MessagingApplication Programming Interface (MAPI) (email), File Transfer Protocol(FTP), HyperText Transfer Protocol (HTTP), Common Internet File System(CIFS) protocol (file transfer), Independent Computing Architecture(ICA) protocol, Remote Desktop Protocol (RDP), Wireless ApplicationProtocol (WAP), Mobile IP protocol, and Voice Over IP (VoIP) protocol.In other embodiments, multi-protocol compression engine 238 providescompression of Hypertext Markup Language (HTML) based protocols and insome embodiments, provides compression of any markup languages, such asthe Extensible Markup Language (XML). In one embodiment, themulti-protocol compression engine 238 provides compression of anyhigh-performance protocol, such as any protocol designed for appliance200 to appliance 200 communications. In another embodiment, themulti-protocol compression engine 238 compresses any payload of or anycommunication using a modified transport control protocol, such asTransaction TCP (T/TCP), TCP with selection acknowledgements (TCP-SACK),TCP with large windows (TCP-LW), a congestion prediction protocol suchas the TCP-Vegas protocol, and a TCP spoofing protocol.

As such, the multi-protocol compression engine 238 acceleratesperformance for users accessing applications via desktop clients, e.g.,Microsoft Outlook and non-Web thin clients, such as any client launchedby popular enterprise applications like Oracle, SAP and Siebel, and evenmobile clients, such as the Pocket PC. In some embodiments, themulti-protocol compression engine 238 by executing in the kernel mode204 and integrating with packet processing engine 240 accessing thenetwork stack 267 is able to compress any of the protocols carried bythe TCP/IP protocol, such as any application layer protocol.

High speed layer 2-7 integrated packet engine 240, also generallyreferred to as a packet processing engine or packet engine, isresponsible for managing the kernel-level processing of packets receivedand transmitted by appliance 200 via network ports 266. The high speedlayer 2-7 integrated packet engine 240 may comprise a buffer for queuingone or more network packets during processing, such as for receipt of anetwork packet or transmission of a network packer. Additionally, thehigh speed layer 2-7 integrated packet engine 240 is in communicationwith one or more network stacks 267 to send and receive network packetsvia network ports 266. The high speed layer 2-7 integrated packet engine240 works in conjunction with encryption engine 234, cache manager 232,policy engine 236 and multi-protocol compression logic 238. Inparticular, encryption engine 234 is configured to perform SSLprocessing of packets, policy engine 236 is configured to performfunctions related to traffic management such as request-level contentswitching and request-level cache redirection, and multi-protocolcompression logic 238 is configured to perform functions related tocompression and decompression of data.

The high speed layer 2-7 integrated packet engine 240 includes a packetprocessing timer 242. In one embodiment, the packet processing timer 242provides one or more time intervals to trigger the processing ofincoming, i.e., received, or outgoing, i.e., transmitted, networkpackets. In some embodiments, the high speed layer 2-7 integrated packetengine 240 processes network packets responsive to the timer 242. Thepacket processing timer 242 provides any type and form of signal to thepacket engine 240 to notify, trigger, or communicate a time relatedevent, interval or occurrence. In many embodiments, the packetprocessing timer 242 operates in the order of milliseconds, such as forexample 100 ms, 50 ms or 25 ms. For example, in some embodiments, thepacket processing timer 242 provides time intervals or otherwise causesa network packet to be processed by the high speed layer 2-7 integratedpacket engine 240 at a 10 ms time interval, while in other embodiments,at a 5 ms time interval, and still yet in further embodiments, as shortas a 3, 2, or 1 ms time interval. The high speed layer 2-7 integratedpacket engine 240 may be interfaced, integrated or in communication withthe encryption engine 234, cache manager 232, policy engine 236 andmulti-protocol compression engine 238 during operation. As such, any ofthe logic, functions, or operations of the encryption engine 234, cachemanager 232, policy engine 236 and multi-protocol compression logic 238may be performed responsive to the packet processing timer 242 and/orthe packet engine 240. Therefore, any of the logic, functions, oroperations of the encryption engine 234, cache manager 232, policyengine 236 and multi-protocol compression logic 238 may be performed atthe granularity of time intervals provided via the packet processingtimer 242, for example, at a time interval of less than or equal to 10ms. For example, in one embodiment, the cache manager 232 may performinvalidation of any cached objects responsive to the high speed layer2-7 integrated packet engine 240 and/or the packet processing timer 242.In another embodiment, the expiry or invalidation time of a cachedobject can be set to the same order of granularity as the time intervalof the packet processing timer 242, such as at every 10 ms.

In contrast to kernel space 204, user space 202 is the memory area orportion of the operating system used by user mode applications orprograms otherwise running in user mode. A user mode application may notaccess kernel space 204 directly and uses service calls in order toaccess kernel services. As shown in FIG. 2, user space 202 of appliance200 includes a graphical user interface (GUI) 210, a command lineinterface (CLI) 212, shell services 214, health monitoring program 216,and daemon services 218. GUI 210 and CLI 212 provide a means by which asystem administrator or other user can interact with and control theoperation of appliance 200, such as via the operating system of theappliance 200 and either is user space 202 or kernel space 204. The GUI210 may be any type and form of graphical user interface and may bepresented via text, graphical or otherwise, by any type of program orapplication, such as a browser. The CLI 212 may be any type and form ofcommand line or text-based interface, such as a command line provided bythe operating system. For example, the CLI 212 may comprise a shell,which is a tool to enable users to interact with the operating system.In some embodiments, the CLI 212 may be provided via a bash, csh, tcsh,or ksh type shell. The shell services 214 comprises the programs,services, tasks, processes or executable instructions to supportinteraction with the appliance 200 or operating system by a user via theGUI 210 and/or CLI 212.

Health monitoring program 216 is used to monitor, check, report andensure that network systems are functioning properly and that users arereceiving requested content over a network. Health monitoring program216 comprises one or more programs, services, tasks, processes orexecutable instructions to provide logic, rules, functions or operationsfor monitoring any activity of the appliance 200. In some embodiments,the health monitoring program 216 intercepts and inspects any networktraffic passed via the appliance 200. In other embodiments, the healthmonitoring program 216 interfaces by any suitable means and/ormechanisms with one or more of the following: the encryption engine 234,cache manager 232, policy engine 236, multi-protocol compression logic238, packet engine 240, daemon services 218, and shell services 214. Assuch, the health monitoring program 216 may call any applicationprogramming interface (API) to determine a state, status, or health ofany portion of the appliance 200. For example, the health monitoringprogram 216 may ping or send a status inquiry on a periodic basis tocheck if a program, process, service or task is active and currentlyrunning. In another example, the health monitoring program 216 may checkany status, error or history logs provided by any program, process,service or task to determine any condition, status or error with anyportion of the appliance 200.

Daemon services 218 are programs that run continuously or in thebackground and handle periodic service requests received by appliance200. In some embodiments, a daemon service may forward the requests toother programs or processes, such as another daemon service 218 asappropriate. As known to those skilled in the art, a daemon service 218may run unattended to perform continuous or periodic system widefunctions, such as network control, or to perform any desired task. Insome embodiments, one or more daemon services 218 run in the user space202, while in other embodiments, one or more daemon services 218 run inthe kernel space.

Referring now to FIG. 2B, another embodiment of the appliance 200 isdepicted. In brief overview, the appliance 200 provides one or more ofthe following services, functionality or operations: SSL VPNconnectivity 280, switching/load balancing 284, Domain Name Serviceresolution 286, acceleration 288 and an application firewall 290 forcommunications between one or more clients 102 and one or more servers106. Each of the servers 106 may provide one or more network relatedservices 270 a-270 n (referred to as services 270). For example, aserver 106 may provide an http service 270. The appliance 200 comprisesone or more virtual servers or virtual internet protocol servers,referred to as a vServer, VIP server, or just VIP 275 a-275 n (alsoreferred herein as vServer 275). The vServer 275 receives, intercepts orotherwise processes communications between a client 102 and a server 106in accordance with the configuration and operations of the appliance200.

The vServer 275 may comprise software, hardware or any combination ofsoftware and hardware. The vServer 275 may comprise any type and form ofprogram, service, task, process or executable instructions operating inuser mode 202, kernel mode 204 or any combination thereof in theappliance 200. The vServer 275 includes any logic, functions, rules, oroperations to perform any embodiments of the techniques describedherein, such as SSL VPN 280, switching/load balancing 284, Domain NameService resolution 286, acceleration 288 and an application firewall290. In some embodiments, the vServer 275 establishes a connection to aservice 270 of a server 106. The service 275 may comprise any program,application, process, task or set of executable instructions capable ofconnecting to and communicating to the appliance 200, client 102 orvServer 275. For example, the service 275 may comprise a web server,http server, ftp, email or database server. In some embodiments, theservice 270 is a daemon process or network driver for listening,receiving and/or sending communications for an application, such asemail, database or an enterprise application. In some embodiments, theservice 270 may communicate on a specific IP address, or IP address andport.

In some embodiments, the vServer 275 applies one or more policies of thepolicy engine 236 to network communications between the client 102 andserver 106. In one embodiment, the policies are associated with aVServer 275. In another embodiment, the policies are based on a user, ora group of users. In yet another embodiment, a policy is global andapplies to one or more vServers 275 a-275 n, and any user or group ofusers communicating via the appliance 200. In some embodiments, thepolicies of the policy engine have conditions upon which the policy isapplied based on any content of the communication, such as internetprotocol address, port, protocol type, header or fields in a packet, orthe context of the communication, such as user, group of the user,vServer 275, transport layer connection, and/or identification orattributes of the client 102 or server 106.

In other embodiments, the appliance 200 communicates or interfaces withthe policy engine 236 to determine authentication and/or authorizationof a remote user or a remote client 102 to access the computingenvironment 15, application, and/or data file from a server 106. Inanother embodiment, the appliance 200 communicates or interfaces withthe policy engine 236 to determine authentication and/or authorizationof a remote user or a remote client 102 to have the application deliverysystem 190 deliver one or more of the computing environment 15,application, and/or data file. In yet another embodiment, the appliance200 establishes a VPN or SSL VPN connection based on the policy engine's236 authentication and/or authorization of a remote user or a remoteclient 103 In one embodiment, the appliance 102 controls the flow ofnetwork traffic and communication sessions based on policies of thepolicy engine 236. For example, the appliance 200 may control the accessto a computing environment 15, application or data file based on thepolicy engine 236.

In some embodiments, the vServer 275 establishes a transport layerconnection, such as a TCP or UDP connection with a client 102 via theclient agent 120. In one embodiment, the vServer 275 listens for andreceives communications from the client 102. In other embodiments, thevServer 275 establishes a transport layer connection, such as a TCP orUDP connection with a client server 106. In one embodiment, the vServer275 establishes the transport layer connection to an internet protocoladdress and port of a server 270 running on the server 106. In anotherembodiment, the vServer 275 associates a first transport layerconnection to a client 102 with a second transport layer connection tothe server 106. In some embodiments, a vServer 275 establishes a pool oftransport layer connections to a server 106 and multiplexes clientrequests via the pooled transport layer connections.

In some embodiments, the appliance 200 provides a SSL VPN connection 280between a client 102 and a server 106. For example, a client 102 on afirst network 102 requests to establish a connection to a server 106 ona second network 104′. In some embodiments, the second network 104′ isnot routable from the first network 104. In other embodiments, theclient 102 is on a public network 104 and the server 106 is on a privatenetwork 104′, such as a corporate network. In one embodiment, the clientagent 120 intercepts communications of the client 102 on the firstnetwork 104, encrypts the communications, and transmits thecommunications via a first transport layer connection to the appliance200. The appliance 200 associates the first transport layer connectionon the first network 104 to a second transport layer connection to theserver 106 on the second network 104. The appliance 200 receives theintercepted communication from the client agent 102, decrypts thecommunications, and transmits the communication to the server 106 on thesecond network 104 via the second transport layer connection. The secondtransport layer connection may be a pooled transport layer connection.As such, the appliance 200 provides an end-to-end secure transport layerconnection for the client 102 between the two networks 104, 104′.

In one embodiment, the appliance 200 hosts an intranet internet protocolor intranetIP 282 address of the client 102 on the virtual privatenetwork 104. The client 102 has a local network identifier, such as aninternet protocol (IP) address and/or host name on the first network104. When connected to the second network 104′ via the appliance 200,the appliance 200 establishes, assigns or otherwise provides anIntranetIP, which is network identifier, such as IP address and/or hostname, for the client 102 on the second network 104′. The appliance 200listens for and receives on the second or private network 104′ for anycommunications directed towards the client 102 using the client'sestablished IntranetIP 282. In one embodiment, the appliance 200 acts asor on behalf of the client 102 on the second private network 104. Forexample, in another embodiment, a vServer 275 listens for and respondsto communications to the IntranetIP 282 of the client 102. In someembodiments, if a computing device 100 on the second network 104′transmits a request, the appliance 200 processes the request as if itwere the client 102. For example, the appliance 200 may respond to aping to the client's IntranetIP 282. In another example, the appliancemay establish a connection, such as a TCP or UDP connection, withcomputing device 100 on the second network 104 requesting a connectionwith the client's IntranetIP 282.

In some embodiments, the appliance 200 provides one or more of thefollowing acceleration techniques 288 to communications between theclient 102 and server 106: 1) compression; 2) decompression; 3)Transmission Control Protocol pooling; 4) Transmission CONTROL Protocolmultiplexing; 5) Transmission Control Protocol buffering; and 6)caching. In one embodiment, the appliance 200 relieves servers 106 ofmuch of the processing load caused by repeatedly opening and closingtransport layers connections to clients 102 by opening one or moretransport layer connections with each server 106 and maintaining theseconnections to allow repeated data accesses by clients via the Internet.This technique is referred to herein as “connection pooling”.

In some embodiments, in order to seamlessly splice communications from aclient 102 to a server 106 via a pooled transport layer connection, theappliance 200 translates or multiplexes communications by modifyingsequence number and acknowledgment numbers at the transport layerprotocol level. This is referred to as “connection multiplexing”. Insome embodiments, no application layer protocol interaction is required.For example, in the case of an in-bound packet (that is, a packetreceived from a client 102), the source network address of the packet ischanged to that of an output port of appliance 200, and the destinationnetwork address is changed to that of the intended server. In the caseof an outbound packet (that is, one received from a server 106), thesource network address is changed from that of the server 106 to that ofan output port of appliance 200 and the destination address is changedfrom that of appliance 200 to that of the requesting client 102. Thesequence numbers and acknowledgment numbers of the packet are alsotranslated to sequence numbers and acknowledgement expected by theclient 102 on the appliance's 200 transport layer connection to theclient 102. In some embodiments, the packet checksum of the transportlayer protocol is recalculated to account for these translations.

In another embodiment, the appliance 200 provides switching orload-balancing functionality 284 for communications between the client102 and server 106. In some embodiments, the appliance 200 distributestraffic and directs client requests to a server 106 based on layer 4 orapplication-layer request data. In one embodiment, although the networklayer or layer 2 of the network packet identifies a destination server106, the appliance 200 determines the server 106 to distribute thenetwork packet by application information and data carried as payload ofthe transport layer packet. In one embodiment, the health monitoringprograms 216 of the appliance 200 monitor the health of servers todetermine the server 106 for which to distribute a client's request. Insome embodiments, if the appliance 200 detects a server 106 is notavailable or has a load over a predetermined threshold, the appliance200 can direct or distribute client requests to another server 106.

In some embodiments, the appliance 200 acts as a Domain Name Service(DNS) resolver or otherwise provides resolution of a DNS request fromclients 102. In some embodiments, the appliance intercepts' a DNSrequest transmitted by the client 102. In one embodiment, the appliance200 responds to a client's DNS request with an IP address of or hostedby the appliance 200. In this embodiment, the client 102 transmitsnetwork communication for the domain name to the appliance 200. Inanother embodiment, the appliance 200 responds to a client's DNS requestwith an IP address of or hosted by a second appliance 200′. In someembodiments, the appliance 200 responds to a client's DNS request withan IP address of a server 106 determined by the appliance 200.

In yet another embodiment, the appliance 200 provides applicationfirewall functionality 290 for communications between the client 102 andserver 106. In one embodiment, the policy engine 236 provides rules fordetecting and blocking illegitimate requests. In some embodiments, theapplication firewall 290 protects against denial of service (DoS)attacks. In other embodiments, the appliance inspects the content ofintercepted requests to identify and block application-based attacks. Insome embodiments, the rules/policy engine 236 comprises one or moreapplication firewall or security control policies for providingprotections against various classes and types of web or Internet basedvulnerabilities, such as one or more of the following: 1) bufferoverflow, 2) CGI-BIN parameter manipulation, 3) form/hidden fieldmanipulation, 4) forceful browsing, 5) cookie or session poisoning, 6)broken access control list (ACLs) or weak passwords, 7) cross-sitescripting (XSS), 8) command injection, 9) SQL injection, 10) errortriggering sensitive information leak, 11) insecure use of cryptography,12) server misconfiguration, 13) back doors and debug options, 14)website defacement, 15) platform or operating systems vulnerabilities,and 16) zero-day exploits. In an embodiment, the application firewall290 provides HTML form field protection in the form of inspecting oranalyzing the network communication for one or more of the following: 1)required fields are returned, 2) no added field allowed, 3) read-onlyand hidden field enforcement, 4) drop-down list and radio button fieldconformance, and 5) form-field max-length enforcement. In someembodiments, the application firewall 290 ensures cookies are notmodified. In other embodiments, the application firewall 290 protectsagainst forceful browsing by enforcing legal URLs.

In still yet other embodiments, the application firewall 290 protectsany confidential information contained in the network communication. Theapplication firewall 290 may inspect or analyze any networkcommunication in accordance with the rules or polices of the engine 236to identify any confidential information in any field of the networkpacket. In some embodiments, the application firewall 290 identifies inthe network communication one or more occurrences of a credit cardnumber, password, social security number, name, patient code, contactinformation, and age. The encoded portion of the network communicationmay comprise these occurrences or the confidential information. Based onthese occurrences, in one embodiment, the application firewall 290 maytake a policy action on the network communication, such as preventtransmission of the network communication. In another embodiment, theapplication firewall 290 may rewrite, remove or otherwise mask suchidentified occurrence or confidential information.

Still referring to FIG. 2B, the appliance 200 may include a performancemonitoring agent 197 as discussed above in conjunction with FIG. 1D. Inone embodiment, the appliance 200 receives the monitoring agent 197 fromthe monitoring service 1908 or monitoring server 106 as depicted in FIG.1D. In some embodiments, the appliance 200 stores the monitoring agent197 in storage, such as disk, for delivery to any client or server incommunication with the appliance 200. For example, in one embodiment,the appliance 200 transmits the monitoring agent 197 to a client uponreceiving a request to establish a transport layer connection. In otherembodiments, the appliance 200 transmits the monitoring agent 197 uponestablishing the transport layer connection with the client 102. Inanother embodiment, the appliance 200 transmits the monitoring agent 197to the client upon intercepting or detecting a request for a web page.In yet another embodiment, the appliance 200 transmits the monitoringagent 197 to a client or a server in response to a request from themonitoring server 198. In one embodiment, the appliance 200 transmitsthe monitoring agent 197 to a second appliance 200′ or appliance 205.

In other embodiments, the appliance 200 executes the monitoring agent197. In one embodiment, the monitoring agent 197 measures and monitorsthe performance of any application, program, process, service, task orthread executing on the appliance 200. For example, the monitoring agent197 may monitor and measure performance and operation of vServers275A-275N. In another embodiment, the monitoring agent 197 measures andmonitors the performance of any transport layer connections of theappliance 200. In some embodiments, the monitoring agent 197 measuresand monitors the performance of any user sessions traversing theappliance 200. In one embodiment, the monitoring agent 197 measures andmonitors the performance of any virtual private network connectionsand/or sessions traversing the appliance 200, such an SSL VPN session.In still further embodiments, the monitoring agent 197 measures andmonitors the memory, CPU and disk usage and performance of the appliance200. In yet another embodiment, the monitoring agent 197 measures andmonitors the performance of any acceleration technique 288 performed bythe appliance 200, such as SSL offloading, connection pooling andmultiplexing, caching, and compression. In some embodiments, themonitoring agent 197 measures and monitors the performance of any loadbalancing and/or content switching 284 performed by the appliance 200.In other embodiments, the monitoring agent 197 measures and monitors theperformance of application firewall 290 protection and processingperformed by the appliance 200.

C. Client Agent

Referring now to FIG. 3, an embodiment of the client agent 120 isdepicted. The client 102 includes a client agent 120 for establishingand exchanging communications with the appliance 200 and/or server 106via a network 104. In brief overview, the client 102 operates oncomputing device 100 having an operating system with a kernel mode 302and a user mode 303, and a network stack 310 with one or more layers 310a-310 b. The client 102 may have installed and/or execute one or moreapplications. In some embodiments, one or more applications maycommunicate via the network stack 310 to a network 104. One of theapplications, such as a web browser, may also include a first program322. For example, the first program 322 may be used in some embodimentsto install and/or execute the client agent 120, or any portion thereof.The client agent 120 includes an interception mechanism, or interceptor350, for intercepting network communications from the network stack 310from the one or more applications.

The network stack 310 of the client 102 may comprise any type and formof software, or hardware, or any combinations thereof, for providingconnectivity to and communications with a network. In one embodiment,the network stack 310 comprises a software implementation for a networkprotocol suite. The network stack 310 may comprise one or more networklayers, such as any networks layers of the Open Systems Interconnection(OSI) communications model as those skilled in the art recognize andappreciate. As such, the network stack 310 may comprise any type andform of protocols for any of the following layers of the OSI model: 1)physical link layer, 2) data link layer, 3) network layer, 4) transportlayer, 5) session layer, 6) presentation layer, and 7) applicationlayer. In one embodiment, the network stack 310 may comprise a transportcontrol protocol (TCP) over the network layer protocol of the internetprotocol (IP), generally referred to as TCP/IP. In some embodiments, theTCP/IP protocol may be carried over the Ethernet protocol, which maycomprise any of the family of IEEE wide-area-network (WAN) orlocal-area-network (LAN) protocols, such as those protocols covered bythe IEEE 802.3. In some embodiments, the network stack 310 comprises anytype and form of a wireless protocol, such as IEEE 802.11 and/or mobileinternet protocol.

In view of a TCP/IP based network, any TCP/IP based protocol may beused, including Messaging Application Programming Interface (MAPI)(email), File Transfer Protocol (FTP), HyperText Transfer Protocol(HTTP), Common Internet File System (CIFS) protocol (file transfer),Independent Computing Architecture (ICA) protocol, Remote DesktopProtocol (RDP), Wireless Application Protocol (WAP), Mobile IP protocol,and Voice Over IP (VoIP) protocol. In another embodiment, the networkstack 310 comprises any type and form of transport control protocol,such as a modified transport control protocol, for example a TransactionTCP (T/TCP), TCP with selection acknowledgements (TCP-SACK), TCP withlarge windows (TCP-LW), a congestion prediction protocol such as theTCP-Vegas protocol, and a TCP spoofing protocol. In other embodiments,any type and form of user datagram protocol (UDP), such as UDP over IP,may be used by the network stack 310, such as for voice communicationsor real-time data communications.

Furthermore, the network stack 310 may include one or more networkdrivers supporting the one or more layers, such as a TCP driver or anetwork layer driver. The network drivers may be included as part of theoperating system of the computing device 100 or as part of any networkinterface cards or other network access components of the computingdevice 100. In some embodiments, any of the network drivers of thenetwork stack 310 may be customized, modified or adapted to provide acustom or modified portion of the network stack 310 in support of any ofthe techniques described herein. In other embodiments, the accelerationprogram 120 is designed and constructed to operate with or work inconjunction with the network stack 310 installed or otherwise providedby the operating system of the client 102.

The network stack 310 comprises any type and form of interfaces forreceiving, obtaining, providing or otherwise accessing any informationand data related to network communications of the client 102. In oneembodiment, an interface to the network stack 310 comprises anapplication programming interface (API). The interface may also compriseany function call, hooking or filtering mechanism, event or call backmechanism, or any type of interfacing technique. The network stack 310via the interface may receive or provide any type and form of datastructure, such as an object, related to functionality or operation ofthe network stack 310. For example, the data structure may compriseinformation and data related to a network packet or one or more networkpackets. In some embodiments, the data structure comprises a portion ofthe network packet processed at a protocol layer of the network stack310, such as a network packet of the transport layer. In someembodiments, the data structure 325 comprises a kernel-level datastructure, while in other embodiments, the data structure 325 comprisesa user-mode data structure. A kernel-level data structure may comprise adata structure obtained or related to a portion of the network stack 310operating in kernel-mode 302, or a network driver or other softwarerunning in kernel-mode 302, or any data structure obtained or receivedby a service, process, task, thread or other executable instructionsrunning or operating in kernel-mode of the operating system.

Additionally, some portions of the network stack 310 may execute oroperate in kernel-mode 302, for example, the data link or network layer,while other portions execute or operate in user-mode 303, such as anapplication layer of the network stack 310. For example, a first portion310 a of the network stack may provide user-mode access to the networkstack 310 to an application while a second portion 310 a of the networkstack 310 provides access to a network. In some embodiments, a firstportion 310 a of the network stack may comprise one or more upper layersof the network stack 310, such as any of layers 5-7. In otherembodiments, a second portion 310 b of the network stack 310 comprisesone or more lower layers, such as any of layers 1-4. Each of the firstportion 310 a and second portion 310 b of the network stack 310 maycomprise any portion of the network stack 310, at any one or morenetwork layers, in user-mode 203, kernel-mode, 202, or combinationsthereof, or at any portion of a network layer or interface point to anetwork layer or any portion of or interface point to the user-mode 203and kernel-mode 203.

The interceptor 350 may comprise software, hardware, or any combinationof software and hardware. In one embodiment, the interceptor 350intercept a network communication at any point in the network stack 310,and redirects or transmits the network communication to a destinationdesired, managed or controlled by the interceptor 350 or client agent120. For example, the interceptor 350 may intercept a networkcommunication of a network stack 310 of a first network and transmit thenetwork communication to the appliance 200 for transmission on a secondnetwork 104. In some embodiments, the interceptor 350 comprises any typeinterceptor 350 comprises a driver, such as a network driver constructedand designed to interface and work with the network stack 310. In someembodiments, the client agent 120 and/or interceptor 350 operates at oneor more layers of the network stack 310, such as at the transport layer.In one embodiment, the interceptor 350 comprises a filter driver,hooking mechanism, or any form and type of suitable network driverinterface that interfaces to the transport layer of the network stack,such as via the transport driver interface (TDI). In some embodiments,the interceptor 350 interfaces to a first protocol layer, such as thetransport layer and another protocol layer, such as any layer above thetransport protocol layer, for example, an application protocol layer. Inone embodiment, the interceptor 350 may comprise a driver complying withthe Network Driver Interface Specification (NDIS), or a NDIS driver. Inanother embodiment, the interceptor 350 may comprise a min-filter or amini-port driver. In one embodiment, the interceptor 350, or portionthereof, operates in kernel-mode 202. In another embodiment, theinterceptor 350, or portion thereof, operates in user-mode 203. In someembodiments, a portion of the interceptor 350 operates in kernel-mode202 while another portion of the interceptor 350 operates in user-mode203. In other embodiments, the client agent 120 operates in user-mode203 but interfaces via the interceptor 350 to a kernel-mode driver,process, service, task or portion of the operating system, such as toobtain a kernel-level data structure 225. In further embodiments, theinterceptor 350 is a user-mode application or program, such asapplication.

In one embodiment, the interceptor 350 intercepts any transport layerconnection requests. In these embodiments, the interceptor 350 executetransport layer application programming interface (API) calls to set thedestination information, such as destination IP address and/or port to adesired location for the location. In this manner, the interceptor 350intercepts and redirects the transport layer connection to a IP addressand port controlled or managed by the interceptor 350 or client agent120. In one embodiment, the interceptor 350 sets the destinationinformation for the connection to a local IP address and port of theclient 102 on which the client agent 120 is listening. For example, theclient agent 120 may comprise a proxy service listening on a local IPaddress and port for redirected transport layer communications. In someembodiments, the client agent 120 then communicates the redirectedtransport layer communication to the appliance 200.

In some embodiments, the interceptor 350 intercepts a Domain NameService (DNS) request. In one embodiment, the client agent 120 and/orinterceptor 350 resolves the DNS request. In another embodiment, theinterceptor transmits the intercepted DNS request to the appliance 200for DNS resolution. In one embodiment, the appliance 200 resolves theDNS request and communicates the DNS response to the client agent 120.In some embodiments, the appliance 200 resolves the DNS request viaanother appliance 200′ or a DNS server 106.

In yet another embodiment, the client agent 120 may comprise two agents120 and 120′. In one embodiment, a first agent 120 may comprise aninterceptor 350 operating at the network layer of the network stack 310.In some embodiments, the first agent 120 intercepts network layerrequests such as Internet Control Message Protocol (ICMP) requests(e.g., ping and traceroute). In other embodiments, the second agent 120′may operate at the transport layer and intercept transport layercommunications. In some embodiments, the first agent 120 interceptscommunications at one layer of the network stack 210 and interfaces withor communicates the intercepted communication to the second agent 120′.

The client agent 120 and/or interceptor 350 may operate at or interfacewith a protocol layer in a manner transparent to any other protocollayer of the network stack 310. For example, in one embodiment, theinterceptor 350 operates or interfaces with the transport layer of thenetwork stack 310 transparently to any protocol layer below thetransport layer, such as the network layer, and any protocol layer abovethe transport layer, such as the session, presentation or applicationlayer protocols. This allows the other protocol layers of the networkstack 310 to operate as desired and without modification for using theinterceptor 350. As such, the client agent 120 and/or interceptor 350can interface with the transport layer to secure, optimize, accelerate,route or load-balance any communications provided via any protocolcarried by the transport layer, such as any application layer protocolover TCP/IP.

Furthermore, the client agent 120 and/or interceptor may operate at orinterface with the network stack 310 in a manner transparent to anyapplication, a user of the client 102, and any other computing device,such as a server, in communications with the client 102. The clientagent 120 and/or interceptor 350 may be installed and/or executed on theclient 102 in a manner without modification of an application. In someembodiments, the user of the client 102 or a computing device incommunications with the client 102 are not aware of the existence,execution or operation of the client agent 120 and/or interceptor 350.As such, in some embodiments, the client agent 120 and/or interceptor350 is installed, executed, and/or operated transparently to anapplication, user of the client 102, another computing device, such as aserver, or any of the protocol layers above and/or below the protocollayer interfaced to by the interceptor 350.

The client agent 120 includes an acceleration program 302, a streamingclient 306, a collection agent 304, and/or monitoring agent 197. In oneembodiment, the client agent 120 comprises an Independent ComputingArchitecture (ICA) client, or any portion thereof, developed by CitrixSystems, Inc. of Fort Lauderdale, Fla., and is also referred to as anICA client. In some embodiments, the client 120 comprises an applicationstreaming client 306 for streaming an application from a server 106 to aclient 102. In some embodiments, the client agent 120 comprises anacceleration program 302 for accelerating communications between client102 and server 106. In another embodiment, the client agent 120 includesa collection agent 304 for performing end-point detection/scanning andcollecting end-point information for the appliance 200 and/or server106.

In some embodiments, the acceleration program 302 comprises aclient-side acceleration program for performing one or more accelerationtechniques to accelerate, enhance or otherwise improve a client'scommunications with and/or access to a server 106, such as accessing anapplication provided by a server 106. The logic, functions, and/oroperations of the executable instructions of the acceleration program302 may perform one or more of the following acceleration techniques: 1)multi-protocol compression, 2) transport control protocol pooling, 3)transport control protocol multiplexing, 4) transport control protocolbuffering, and 5) caching via a cache manager. Additionally, theacceleration program 302 may perform encryption and/or decryption of anycommunications received and/or transmitted by the client 102. In someembodiments, the acceleration program 302 performs one or more of theacceleration techniques in an integrated manner or fashion.Additionally, the acceleration program 302 can perform compression onany of the protocols, or multiple-protocols, carried as a payload of anetwork packet of the transport layer protocol. The streaming client 306comprises an application, program, process, service, task or executableinstructions for receiving and executing a streamed application from aserver 106. A server 106 may stream one or more application data filesto the streaming client 306 for playing, executing or otherwise causingto be executed the application on the client 102. In some embodiments,the server 106 transmits a set of compressed or packaged applicationdata files to the streaming client 306. In some embodiments, theplurality of application files are compressed and stored on a fileserver within an archive file such as a CAB, ZIP, SIT, TAR, JAR or otherarchives In one embodiment, the server 106 decompresses, unpackages orunarchives the application files and transmits the files to the client102. In another embodiment, the client 102 decompresses, unpackages orunarchives the application files. The streaming client 306 dynamicallyinstalls the application, or portion thereof, and executes theapplication. In one embodiment, the streaming client 306 may be anexecutable program. In some embodiments, the streaming client 306 may beable to launch another executable program.

The collection agent 304 comprises an application, program, process,service, task or executable instructions for identifying, obtainingand/or collecting information about the client 102. In some embodiments,the appliance 200 transmits the collection agent 304 to the client 102or client agent 120. The collection agent 304 may be configuredaccording to one or more policies of the policy engine 236 of theappliance. In other embodiments, the collection agent 304 transmitscollected information on the client 102 to the appliance 200. In oneembodiment, the policy engine 236 of the appliance 200 uses thecollected information to determine and provide access, authenticationand authorization control of the client's connection to a network 104.

In one embodiment, the collection agent 304 comprises an end-pointdetection and scanning mechanism, which identifies and determines one ormore attributes or characteristics of the client. For example, thecollection agent 304 may identify and determine any one or more of thefollowing client-side attributes: 1) the operating system an/or aversion of an operating system, 2) a service pack of the operatingsystem, 3) a running service, 4) a running process, and 5) a file. Thecollection agent 304 may also identify and determine the presence orversions of any one or more of the following on the client: 1) antivirussoftware, 2) personal firewall software, 3) anti-spam software, and 4)internet security software. The policy engine 236 may have one or morepolicies based on any one or more of the attributes or characteristicsof the client or client-side attributes.

In some embodiments, the client agent 120 includes a monitoring agent197 as discussed in conjunction with FIGS. 1D and 2B. The monitoringagent 197 may be any type and form of script, such as Visual Basic orJava script. In one embodiment, the monitoring agent 129 monitors andmeasures performance of any portion of the client agent 120. Forexample, in some embodiments, the monitoring agent 129 monitors andmeasures performance of the acceleration program 302. In anotherembodiment, the monitoring agent 129 monitors and measures performanceof the streaming client 306. In other embodiments, the monitoring agent129 monitors and measures performance of the collection agent 304. Instill another embodiment, the monitoring agent 129 monitors and measuresperformance of the interceptor 350. In some embodiments, the monitoringagent 129 monitors and measures any resource of the client 102, such asmemory, CPU and disk.

The monitoring agent 197 may monitor and measure performance of anyapplication of the client. In one embodiment, the monitoring agent 129monitors and measures performance of a browser on the client 102. Insome embodiments, the monitoring agent 197 monitors and measuresperformance of any application delivered via the client agent 120. Inother embodiments, the monitoring agent 197 measures and monitors enduser response times for an application, such as web-based or HTTPresponse times. The monitoring agent 197 may monitor and measureperformance of an ICA or RDP client. In another embodiment, themonitoring agent 197 measures and monitors metrics for a user session orapplication session. In some embodiments, monitoring agent 197 measuresand monitors an ICA or RDP session. In one embodiment, the monitoringagent 197 measures and monitors the performance of the appliance 200 inaccelerating delivery of an application and/or data to the client 102.

In some embodiments and still referring to FIG. 3, a first program 322may be used to install and/or execute the client agent 120, or portionthereof, such as the interceptor 350, automatically, silently,transparently, or otherwise. In one embodiment, the first program 322comprises a plugin component, such an ActiveX control or Java control orscript that is loaded into and executed by an application. For example,the first program comprises an ActiveX control loaded and run by a webbrowser application, such as in the memory space or context of theapplication. In another embodiment, the first program 322 comprises aset of executable instructions loaded into and run by the application,such as a browser. In one embodiment, the first program 322 comprises adesigned and constructed program to install the client agent 120. Insome embodiments, the first program 322 obtains, downloads, or receivesthe client agent 120 via the network from another computing device. Inanother embodiment, the first program 322 is an installer program or aplug and play manager for installing programs, such as network drivers,on the operating system of the client 102.

D. GSLB Batchable and Hierarchical Site Configuration

Referring now to FIG. 4A, an embodiment of an environment of amulti-site deployment of appliances is depicted. In brief overview, thedeployment may include a plurality of sites, such as Site A, Site B,Site C, Site D, Site and Site F. Each of the sites may include one ormore appliances 200A-200F. A client 102 may access or communicate withany one or more servers via any one or more appliances. Each of theseappliances may provide any type and form of services, control ormanagement of the client's access to one of more servers 106A-106N. Anyof the appliances may communicate with any other appliance or a clientvia one or more networks 104-104′.

In further details of the example embodiment of FIG. 4A, Site Acomprises appliance 200A managing multiple servers, server Svr-A1through server Svr-A2. Site B comprises appliance 200B managing multipleservers, server Svr-B1 through server Svr-B2. Site C comprises appliance200C managing multiple servers, server Svr-C1 through server Svr-C2.Site D comprises appliance 200D managing multiple servers, server Svr-D1through server Svr-D2. Site E comprises appliance 200E managing multipleservers, server Svr-E1 through server Svr-E2 and Site F comprisesappliance 200F managing multiple servers, server Svr-F1 through serverSvr-F2.

In some embodiments, the multi-site deployment of FIG. 4 may represent aglobal server load balancing (GSLB) deployment. One or more of theappliances may be configured or designed and constructed to provideglobal server load balancing, and sometimes are referred to GSLB or GSLBappliances. A GSLB appliance may be designed and configured to receivedDNS requests from clients and resolve the domain name of the request toan internet protocol address of a selected appliance 200A-200F at any ofthe sites A-F. In processing the DNS request, the GSLB appliance may useany type and form of load balancing scheme to select a desired siteand/or appliance for processing or handling a client request. By way ofexample, Site A appliance 200A and Site B appliance 200B may beconfigured as GSLB appliances which load balance clients and clientrequest among Sites C, D, E and F, and in some embodiments, theappliances 200A and 200B also.

Any of the sites and appliances of the environment may be arranged,configured or deployed in any type and form of hierarchical or parent,child and/or peer relationship. Any one appliance or site may be a peerto another appliance or site. For example, appliance 200A may be a peerto appliance 200B for providing GSLB domain resolution services. Any oneappliance or site may be a parent node of another appliance or site. Forexample, appliance 200A at Site A may be a parent site or appliance toappliance 200D of Site D. Any one appliance or site may be a child nodeof another appliance or site. For example appliance 200F at Site F maybe a child node to Site B and appliance B.

Each of the appliances may be configured the same or differently fromany other appliance. In some embodiments, multiple appliances providingGSLB domain name services may be configured the same. In otherembodiments, multiple appliances providing GSLB domain name servicingmay be configured differently. A Site may have multiple appliances, eachappliance configured the same or differently. Appliances at one Site maybe configured the same or differently as appliances at another site. Inview of the functionality of an appliance previously described inconnection with FIG. 2B, one appliance may be configured to providedacceleration and content switching while another appliance may beconfigured to provide AppFw and SSL VPN functionality. An appliance maybe configured to provide the functionality of any of the embodiments ofthe appliance described herein, such as in conjunction with FIGS. 2A and2B. In some embodiments, heterogeneous appliances may be deployed. Forexample, a first appliance may be provided as a product of a firstmanufacturer and a second appliance may be provided as a product ofsecond manufacturer. In other embodiments, homogenous appliances may bedeployed in which any version of the appliance is supplied by the samemanufacturer. In some embodiments, any combination of heterogeneous andhomogenous appliances may be deployed.

Referring now to FIG. 4B, an embodiment of an appliance to provide abatchable and/or hierarchical configuration of appliances in amulti-site deployment is depicted. In brief overview, the appliance 200Amay comprise any embodiment of a vServer 275. The appliance and/orvServer may be configured to provide GSLB services for a multi-sitedeployment, such as load balancing Site B and Site C via one or morenetworks 104. The appliance may include a configurator 410. Theconfigurator 410 may further include master/slave identification 415, asite hierarchy configuration 420 and a distributor 425. Via theconfigurator 410, the appliance may be identified as a master node bythe master/slave identifier 415. The appliance 200A may be configured tohave a site hierarchy configuration 420 comprising identification andconfiguration of all the nodes in the multi-site deployment, such as inFIG. 4A. This site hierarchy configuration 420 may be distributed,applied or published to other appliances via a distributor 425.

In further details, the configurator 410 may comprise any type and formof function, operations or logic for configuring a vServer 275. Theconfigurator 410 may comprise software, hardware of any combination ofsoftware and hardware. The configurator 310 may comprise an application,program, library, script, process, service, task, thread or set ofexecutable instructions. The configurator may comprise any type and formof user interface. In one embodiment, the configurator 410 comprises acommand line interface. In another embodiment, the configurator 410comprises a graphical user interface. In some embodiments, theconfigurator 410 comprises a graphical user interface and a command lineinterface. The configurator 410, for example, may include the CLI 212and/or GUI 210 of embodiments of the appliance described in conjunctionwith FIG. 2B. In some embodiments, the configurator is part of thevServer 275. In other embodiments, the configurator interfaces to orcommunicates with vServer 275.

The configurator 410 may configure any of the features, operations orfunctionality of any of the embodiments of the appliance describedherein. The configurator 410 may establish and/or configure one or morevServers 275 of an appliance. The configurator 410 may identify theservers and services that each vServer manages. In some embodiments, theconfigurator 410 establishes and configures a vServer to be a GSLBvServer that provides GSLB load balancing. The configurator 410 mayidentify services provided via other appliances as a remote service ofthe GSLB server. In other embodiments, the configurator 410 establishesand configures a vServer to be a load balancing vServer, such as forservers at a Site. The configurator 410 may identify on the appliancethe services of the servers managed by the appliance.

The configurator 410 may configure a site hierarchy 420 for amulti-appliance or multi site deployment. The site hierarchy 420identify the relationships between sites and/or appliances of sites in amulti-site deployment, such as for GSLB. For example, the configurator410 may identify which appliances, sometimes referred to nodes, areparent, child and/or peer nodes. In some embodiments, a user via theconfigurator identifies an appliance as a parent site. In someembodiments, the user configures and identifies multiple parent sites.In some embodiments, the user identifies and configures one or more peernodes as the top of a hierarchy of sites. The user may further identifyand configure child nodes to these top peer nodes, which in turn mayparent nodes to other appliances. In one embodiment, the user identifiesand configures one or more appliances as child nodes to any one or moreparent nodes. In some of these embodiments, the user identifies andconfigures a child node to be a parent to other children nodes. In someembodiments, one or more parent nodes below the top nodes may also bepeer nodes. In another embodiment, one or more child nodes may also bepeer nodes.

The site hierarchy 420 may be defined, specified or configured using anytype and form of commands, instructions or data. These command,instructions or data may in a form readable, accessible or otherwiseunderstood by the appliance and/or vServer. In some embodiments, thesite hierarchy 420 comprises a set of configuration commands. In someembodiments, the site hierarchy 420 may comprise textual instructionsand data. For example, in one embodiment, the site hierarchy 420 is afile. In some embodiments, the site hierarchy 430 comprises a list ofcommand line commands or instructions to be processed by a userinterface, such as CLI, of the appliance. In another embodiment, thesite hierarchy 420 comprises one or more scripts or executables. In someembodiments, the site hierarchy 420 references or includes a referenceto any one or more files. In many embodiments, the site hierarchy 420includes one or more application programming interface (API) calls. Thesite hierarchy 420 may be batchable in that a single configuration orfile may be executed, run or established on a plurality of appliances.

The configurator 410 may include any type and form of mechanism 415 foridentifying an appliance or vServer as a master node or slave node. Themaster identifier 415 may include any configuration data, setting, flagor parameter providing an identification of master. In some embodiments,a user may set a flag or parameter to identify the node as a master orslave. For example, in one embodiment, the user may selected a userinterface element of a GUI to identify the appliance as a master. Inanother embodiment, the user may pass a parameter, value or set a flagon a command line command via the CLI to identify the node as master. Inother embodiments, the site hierarchy 430 comprises data orconfiguration command to set a node as a master. In some embodiments, ifthe appliance is not identified as a master node then by default andwithout specific identification the appliance may be a slave node. Inanother embodiment, the appliance a user selects to perform theconfiguration for the multi-site deployment may be considered themaster. In some embodiments, any of the peer GSLB nodes may be a masternode. In another embodiment, multiple nodes may be a master node. Insome cases, one node may be a backup master node to another node.

The distributor 425 may comprise any logic, operations or functionalityto publish, distribute or otherwise provide a configuration to anappliance. In some embodiments, the distributor comprises any type andform of communication interface between appliances or between anothercomputing device and the appliance. In some embodiments, the distributormay download, upload or file transfer a configuration file to anappliance. In other embodiments, the distributor may email aconfiguration to a computing device or appliance. In some embodiments,the distributor makes remote procedure calls, such as remote shell callsfrom one appliance to another appliance to distribute the configuration.In another embodiments, the distributor may write configuration to anytype and form of computer readable medium. In another embodiments, theconfiguration is distributed via a connection and a protocol supportedby the appliances, such as the Metric Exchange Protocol (MEP) describedbelow. The distributor may distribute configuration via a secure call,command or connection, such as for example, a secure SSH, a secure copySCP or a secure file transfer protocol (SFTP).

The interface 435 may comprise any logic, operations or functionality toreceive and apply configuration information. In some embodiments, theinterface may receive any configuration via a file. In anotherembodiment, the interface may receive a configuration via a metricexchange connection. In some embodiments, the interface may receive aconfiguration distributed by a distributor using any of the interfacemechanism described above in conjunction with the distributor. In oneembodiment, the interface may receive or apply configuration via anytype and form of remote command, procedure or API calls. The interfacemay apply configuration to an appliance via a secure call, command orconnection, such as for example, a secure SSH, a secure copy SCP or asecure file transfer protocol (SFTP). In some embodiments, the interfacemay received and apply configuration from a user via a graphical userinterface or command line interface. In some embodiment, the interfaceis separate and distinct from the distributor. In other embodiment, theinterface and distributor are combined into the same unit, logic orfunctionality.

An appliance may communicate with another appliance via any type andform of protocol. In some embodiments and as illustrated in FIG. 4B, theappliances communicate using any form of a metric exchange protocol(MEP), such as the MEP protocol provided by NetScaler appliancesmanufactured by Citrix Systems, Inc. of Ft. Lauderdale, Fla. The metricexchange protocol may be any transport layer protocol, any presentationlayer protocol or any application layer protocol. In one embodiment, theappliances uses a Simple Network Management Protocol (SNMP) forcommunications. In another embodiment, the appliances use a commonmanagement information protocol (CIMP). Any of these protocols may beused by the appliances to communicate, exchange or provide any type andform of information, data, metrics and/or statistics about theconfiguration, performance and/or operation of the appliance or anycomponent thereof. In some embodiments, the appliance with the lowerinternet protocol address initiates the connection or makes theconnection request. In other embodiments, the appliance with the higherinternet protocol address initiates the connection or makes theconnection request. In yet another embodiment, the appliance identifiedfirst or identified as a parent initiates the connection or makes theconnection request. In one embodiment, the appliance identified as achild initiates or makes the connection request.

Referring now to FIG. 4C, an embodiment of a multi-appliance andmulti-site deployment is depicted. In brief overview, this multi-siteconfiguration is based on a peer to peer relationship among all of thesites and appliances. Site A and appliance 200A is a peer node to eachof the appliances at Sites B-F. Likewise, each of Site B, C, D and F arepeer nodes to the other sites. Each appliance at each site has aseparate and distinct configuration 420A-N. Based on the configurationand the peer to peer relationship, each appliance establishes and has ametric exchange connection with each of the peer appliances. In thisembodiment of a type of hierarchy and configuration, all the appliancesare communicating with and need to be configured to communicate withevery other appliance.

In the example embodiment of FIG. 4C, each of the appliances haveseparate configuration. By way of example, the following table shows aconfiguration or portion thereof to identify each of the sites and nodesin the hierarchy of the multi-site deployment. The add commandillustrated below has a syntax of:

add gslb<site identifier> <internet protocol address>

This command adds a site to a gslb configuration and identifies the siteby a site identifier and an internet protocol address. Any type and formof site identifier may be used including any text, numerics oralphanumeric based characters. The IP address may be any desired orsupported IP address available via the networks of the deployment.

# Configuration on Site A 420A add gslb site-A IP-A add gslb site-B IP-Badd gslb site-D IP-D add gslb site-E IP-E add gslb site-C IP-C #Configuration on Site B 420B add gslb site-A IP-A add gslb site-B IP-Badd gslb site-C IP-C # Configuration on Site-C 420C add gslb site-A IP-Aadd gslb site-B IP-B add gslb site-C IP-C add gslb site-F IP-F #Configuration on Site D 420D add gslb site-A IP-A add gslb site-D IP-D #Configuration on Site E 420E add gslb site-A IP-A add gslb site-E IP-E #Configuration on Site-F 420F add gslb site-C IP-C add gslb site-F IP-FThe above configuration lists a set of configuration commands in aformat for an example embodiment of the appliance as a NetScalerappliance. Any other type and format of command or instruction may beused. As noted by each of the site specific configurations 420A-420F, insome embodiments, each site may only have a partial or limited view ofthe entire topology or GSLB hierarchy.

Referring now to FIG. 4D, another embodiment of a multi-site deploymentis depicted. In this embodiment, a centralized or single configuration420 is used to configure the site hierarchy of each appliance. In thismanner, each of the appliances may leverage a single configuration 420to identify and understand the site hierarchy. In brief over, the sitehierarchy of FIG. 4D includes three peering Sites A, B and Cparticipating in GSLB. Sites D, E and F comprises sites acting as childnodes to one of the peering nodes.

For the topology depicted in FIG. 4D, the site hierarchy configurationmay use an option for defining a site called the “parentSite”. TheparentSite identifies for a child node the site identifier of anestablished site, the parent node. With this option, a configuration canbe created that will be batch-able across all the sites.

420 # Define the 3 peering sites A, B, C participating in GSLB. add gslbsite-A IP-A add gslb site-B IP-B add gslb site-C IP-C # Define the sitesacting as child nodes: D, E, F add gslb site-D IP-D-parentSite Site-Aadd gslb site-E IP-E-parentSite Site-A add gslb site-F IP-F-parentSiteSite-CEach of the appliances 200A-200F may execute and configure one or morevServers based on the site hierarchy configuration 420. Althoughillustrated with a format and parameter referred to as parentSite, otherembodiments may uses parameter options to identify child nodes, suchas—childSite or to identify peer nodes such as—peerSite.

With these options to identify nodes of a site hierarchy as peer, childand/or parent, the same configuration provides the logical relationshipbetween sites and provides all the appliances with a complete GSLB sitetopology. With this type of site hierarchy configuration, each siteknows which other sites to connect with. In some embodiments, this sitehierarchy configuration identifies the immediate sites an appliance mayreach via a network to connect with. In some embodiments, this type ofsite hierarchy configuration identifies those appliances or sits forreceived metrics or statistics via a metric exchange connection, such asa particular GSLB service's statistics. With this type of site hierarchyconfiguration which is batchable, in some embodiments, there may be nochange made by a an administrator to the configuration that is deployed.That is, in some embodiments, the same GSLB site hierarchy configurationis applied to all of the appliances in the topology.

As illustrated in FIG. 4D, the number of connections between applianceshas been reduced. With the site hierarchy configuration 420 identifiedthe entire GSLB topology, every site and appliance has knowledge of thetotal site topology. With this information, an appliance may determine adesired or optimized metric exchange connectivity with other appliances.For example, in some embodiments, an appliance of child site onlyconnects to an appliance of a parent site. In some embodiments, a parentsite connects to peers that are patents and to any direct childrennodes.

In some embodiments, a child site makes an metric exchange connection toa parent site. For example, appliance 200E at Site E may providestatistics via a connection to patent site of appliance 200A of Site A.The GSLB vServer of appliance 200A may use these statistics to performload balancing among the sites. In some embodiments, the child site doesconnect to another child site. For example, appliance 200E may notconnect to appliance 200D. In one embodiment, the child site does notaccept any connections from a non-parent Site. For example, if appliance200D attempts to connect to appliance 200E, the appliance 200E mayreject, drop or otherwise not accept the connection request. In someembodiments, the child site only accepts connections from a directparent site. In other embodiments, the child site accepts connectionsfrom another child site, a peer site or an indirect parent site.

For GSLB load balancing, statistics of the peer sites may be exchanged.For example, in FIG. 4D, appliance 200 A of Site and appliance 200B ofSite B and appliance 200C of Site C each have a metric exchangeconnection to each other. For statistics of services on child sites ofpeers, the parent sites provide this information. For example, appliance200A obtains statistics from child sites appliance 200D and appliance200E. Appliance 200A exchanges with appliances 200B and 200C thestatistics from appliances 200D and 200E. Likewise, appliance 200Cobtains statistics from appliance 200F and provides these statistics toappliances 200B and 200A. If a site or appliance does not identify aparent site, in some embodiments, the appliance identifies all sites aspeers and connects to each of these sites.

If none of the sites configured has a parentSite, then all sites areconsidered as peers and every site has a metric exchange connection tothe other.

In some embodiments, the hierarchy may have any number of levels. Inother embodiments, the hierarchy may be limited to a predeterminednumber of levels. In one embodiments, a site hierarchy may be limited tototal number of 32 sites participating in GSLB. By way of an exampleembodiment, the following are the characteristics of a site at aparticular layer or level in the hierarchy.

An Embodiment of a GSLB Site Configuration (e.g., a Parent Site):

1. DNS Config Optional with a There should be a predetermined number ofsites predetermined for example, 2 sites that have DNS minimumconfiguration. DNS config allows for queries routed to these sites to beanswered for domains that the appliance 200 does GSLB. 2. LB ConfigOptional These sites can have load balancing, content switching or cacheredirection configuration of the IP's participating in GSLB. In someembodiments, the may also not have any LB config also. In this case,they have all gslb services as remote services and may also have a DNSconfig. 3. GSLB Config In some GSLB Config 420 specifies the siteembodiments, configuration and identifies MEP connections to requiredestablish. MEP allows for stats to be collected So that when DNS queriesare received, a decision can be made. To be given to other peers ifasked for. 4. MEP Established A GSLB Sites established MEP to:Connections Peer GSLB (parent) Sites Direct child sites. 5. MaximumPredetermined There can be a predetermined maximum number of amount ofsites in a given gslb config. sites, such as 32An Embodiment of LB Site Configuration (e.g., Child Sites)

1. DNS Config In some In one embodiments, there is not any not anyembodiments, DNS configuration on these sites. In some not-Requiredembodiments, The design of the site config should be such that thereshould be not be necessary for a child site to have to process DNSqueries. 2. LB Config In some These sites have LB/CS/CR config of theIP's embodiments, participating in GSLB. Required 3. GSLB Config In someOnly basic gslb config is required on the child site. embodiments, OnlyAdd gslb site is done the child so that the Basic child site knows theparent site to connect to. 4. MEP Established A LB Site establishes MEPto a parent site. Connections 5. Maximum A There can be a predeterminedmaximum number of predetermined sites, such as 1024 maximum, such as1024Although at times the site hierarchy is referenced to in the context ofGSLB as a GSLB site hierarchy, many embodiments of the systems andmethods described herein are applied to a multi-site or multi-appliancedeployment regardless if a GSLB context/environment or not.

Referring now to FIG. 4E, an embodiment of a method of deploying a sitehierarchy via a batchable configuration to each of the appliances in amulti-appliance deployment is depicted. In brief overview, at step 480,a GSLB site configuration is configured or provided on an applianceidentified as a master node. At step 482, each of the appliances in themultiple sites receives a copy of the GSLB site hierarchy configuration.At step 484, each of the appliances apply the GSLB site hierarchyconfiguration and identify itself in the configuration. At step 486,each of the appliances identifies peer information from the GSLB sitehierarchical configuration and step 488, each of the applianceidentifies parent and child information from the GSLB site hierarchyconfiguration. At step 490, appliances establish metric exchangeconnections responsive to the configuration.

In further details, at step 480, a user may configure any type and formof site hierarchy, such as a GSLB site hierarchy, on any appliance in amulti-site deployment. A user may define or specify any topology for aGSLB site hierarchy with any combination of one or more peer sites,parent sites and/or child sites. In some embodiments, the user defines asite hierarchy with a single top node. In other embodiments, the userdefines a site hierarchy with multiple peers nodes at the top of thehierarchy. The user may specify in the site hierarchy any number oflevels of parent and child nodes. Each peer node may be a parent to anynumber of sites. Each site that is a child of a top node may also beparent node having any number of children and each child may further bea parent to any number of further children nodes.

A user, such as an administrator, may identify any appliance of any siteas a master node for configuring the site hierarchy. In someembodiments, the user identifies a top node as a master node. In anotherembodiment, the user identifies an appliance that is a child of a parentsite as the master node. In some embodiments, the user identifies aplurality of appliances as master nodes. In some cases, an appliance isdesignated as a backup master node. In some embodiments, the userspecifies via configuration of the appliance that the appliance is amaster. In another embodiment, an appliance is considered a master nodebecause the user configures the site hierarchy on that appliance.

At step 482, any of the other appliances in the site hierarchy mayreceive a copy of the site hierarchy from a user, the master node orotherwise from another appliance. In some embodiments, a user or theappliance may distribute the site hierarchy 420 of the master node toeach of the other appliances of the multi-site deployment. In someembodiments, the user transfers an electronic or computer readable copyof the site hierarchy via a computer readable medium from one applianceto another appliance. In one embodiment, a user configures any otherappliance via the configuration on that appliance, such as via the CLIor GUI of the appliance. In another embodiment, the user or the masternode publishes or distributes the site hierarchy via the distributor425. In some embodiments, the user or the master node applies the sitehierarchy to one or more appliances via the interface 435.

At step 484, each of the appliances receiving the site hierarchyexecutes or otherwise applies the configuration. An interface 435 oneach appliance may receive the site hierarchy configuration and executeor apply each configuration command. The configurator 410 on eachappliance may receive and apply each configuration command of the sitehierarchy configuration. In some embodiments, the appliance or anyportion thereof executes the site hierarchy configuration as a batchablescript via the CLI of the appliance. In other embodiments, theconfiguration executes the site hierarchy as a batchable set ofconfiguration commands. For example, either a CLI or GUI of theappliance may read in a site hierarchy configuration file and processeach line in the file a configuration command. In some embodiments, anAPI call to the configurator causes the configurator to apply each ofthe configuration commands in the site hierarchy configuration.

The appliance applying the configuration may determine or recognize anyreferences to the site identifier supported, hosted or otherwiseprovided via the appliance. The appliance may comprise any configurationthat identifies an identifier of the site of the appliance. For example,the appliance 200A of Site A may have an identifier of Site A configuredfor the appliance. In some embodiments, the configurator or interface ofthe configuration when processing the site hierarchy configurationdetermines the one or more configuration commands that reference thesite identifier configured for that appliance. In other embodiments, theconfigurator or interface of the appliance determines any configurationcommands in the site hierarchy that reference the IP address supported,hosted or otherwise provided via the appliance. For example, appliance200C may recognize that IP address IP-C is the IP address for itselfwhen applying the site hierarchy configuration. In another embodiments,the appliances may use a combination of site identifier and IP addressto recognize the configuration commands reference itself. In any ofthese manners, an appliance may determine where in the site hierarchythe appliance is configured based on the recognition of the appliancessite identifier and/or IP address.

Based on this and any of the other Site, parent, peer and/or childinformation from the configuration, the appliance may determine anentire topology of the site represented by the site hierarchyconfiguration. In some embodiments, the appliance may determine based onorder or location of configuration commands in the configuration thetopology of the site. In some embodiments, the appliance may determinevia the configuration based on parameters or options of configurationcommands or lack thereof, the site topology. The appliance such as viaconfiguration may store this site topology in any manner, such as viadata structures or files, in memory or storage. In some embodiments, theappliance uses a tree based data structure for representing the sitehierarchy.

At step 486, each of the appliances identifies any peer nodes from theconfiguration. During, upon or after applying the site hierarchyconfiguration, the appliance, such as via configurator, may determinethe site identifier and/or IP address of any peer nodes to itself. Forexample, any top level GSLB site, such as Sites A, b and C in FIG. 4Dmay determine the other Sites at the same level in the hierarchy. Insome embodiments, the appliance determines those Sites not identifyingany parent sides as the top level peer nodes. An appliance at any levelbelow the top level may identify other peer nodes, such as child nodeswhich share the same parent node. Being full topology aware, theappliance may configure, perform or operate based on the topology. Forexample, the appliance may monitor services based on the topology. Inanother example, the appliance may establish and share metrics based onthe topology.

At step 488, each of the appliances identifies parent and/or childinformation from the configuration. During, upon or after applying thesite hierarchy configuration, the appliance, such as via configurator,may determine the site identifier and/or IP address of any siteidentified as a parent. In some embodiments, a direct parent of a siteis identified via a configuration parameter, such as for example,parentSite. In some embodiments, the appliance determines any siteidentified via a parent site identifier, including those Sites which arenot a direct parent to the current appliance. During, upon or afterapplying the site hierarchy configuration, the appliance, such as viaconfigurator, may determine the site identifier and/or IP address of anysite identified or determined to be a child. For example, anconfiguration command that specifies a parent Site may include a siteidentifier and/or IP address of the node that is a child node.

At step 490, each of the appliances established metric exchangeconnection responsive to the GSLB site hierarchy represented by theconfiguration. Upon applying the GSLB site hierarchy configuration tothe appliances deployed for the multi-sites, each of the sites andappliances thereof have a representation of the entire topology. Basedon the recognized topology and the configuration of the appliance, eachappliance may establish metric exchange connections with otherappliances according to the site hierarchy. In some embodiments, anappliance of a child site establishes a connection with an appliance ofa parent site. In some embodiments, an appliance of a parent Siteestablishes a connection with each child Site. In another embodiment,each appliance of peer Sites establishes a connection with each peer. Insome embodiments, depending on and/or responsive to the topology, anappliance may not accept a connection from another appliance. Forexample, an appliance of a child Site to a first parent site may notaccept a connection from a child Site of a second parent site. In thismanner, the appliances for the multi-site deployment may moreefficiently establish metric exchange connections and share metrics inmanner driven by the topology.

E. GSLB Auto Synchronization

Referring now to FIGS. 5A and 5B, systems and methods forsynchronization configuration between appliances are depicted. A userdriven approach may used to configure an appliance identified as amaster node and synchronize that configuration of master node with otherappliances. For example, as described in connection FIGS. 4A-4E, a usermay configure a site hierarchy 420. With the systems and methods ofFIGS. 5A and 5B, the user may synchronize each of the appliances of amulti-site deployment to use the site hierarchy configuration of themaster node.

In a general over, this synchronization solution involves identifying asite as the master GSLB node. All the other nodes in the topology mayautomatically become slaves of this master node. The master node may getthe currently running GSLB configuration of each of the slave nodes. Forexample, the master node may be configured to login to each of the slavenodes. Each of these configuration are compared with the currentlyrunning configuration of the master node. The master node generates aconfiguration command set for each slave node that can be applied on theslave node to get the GSLB configuration of the slave the same as themaster node. The master node then applies each of these generatesconfiguration command sets to the corresponding slave node.

Referring now to FIG. 5A, an embodiment of an appliance forsynchronizing a configuration between appliances in a multi-appliance ormulti-site deployment is depicted. In brief overview, appliances 200A,200N and 200N may be deployed in a multi-site environment. Appliance200A may be deployed at Site A while appliance 200B is deployed at SiteB and appliance 200C, at Site C. In this example embodiment, appliance200A may be designed via the master identifier 415 as a master node. Auser may configure a site hierarchy 420 via the configuration 410. Theinterface 425 of the configuration may obtain the configurations 420B-Cfrom each of appliance 200B and 200C. The comparator 510 compares eachof the received configurations 420B and 430C with the configuration 420of the master node. A generator 515 responsive to the comparatorgenerates a configuration command set 520B and 520C for each appliance.The master node 200A may apply via the interface 435 each of theseconfiguration command sets 520A-520N to the corresponding appliance tosynchronize each slave appliance configuration with the master applianceconfiguration.

In further details, the configurator 410 may comprise any embodiments ofthe master/slave mechanism 415, site hierarchy 420 and the interface 425described above in connection with FIGS. 4A-4E.

In further embodiments, the interface 420 may be designed andconstructed to authenticate and/or login to an appliance using anyauthentication techniques and mechanism. In some embodiments, theappliance may be configured to use a user identifier and password tologin via the interface to another appliance, such as via a secondinterface of a second appliance. In some embodiments, an appliance isconfigured with a predetermined user id and password pair to use tologin to another appliance. For example, an appliance being logged intomay include and identify a userid and password for any other appliance.In some embodiments, to avoid providing a password by the master tologin each time to a slave, the appliances may have master-slave pairsto auto-login using any type and form of public-key authenticationmethods. In some embodiments, predetermined, special or internal userids may be used that do not have passwords.

In some embodiments, the interface may comprise initiating or executingany type and form of script on an appliance. In some embodiments, theinterface may execute a perl, awk or sed script. The interface may makeany local or remote system calls, such as via the script or via an API.The interface may make system calls to an operating system of theappliance. In some embodiments, the interface may make an API call toany application or program of the appliance. In one embodiment, theinterface uses a remote CLI functionality to access and obtaininformation from a remote appliance. In some embodiments, theconfigurator determinations that a slave or remote node is not to besynchronized. For example, one site node specifies via configuration ormetric exchange that is not selected to be part of a synchronizationprocess. In some embodiments, a site appliance may provide informationindicating that the configuration on that appliance should not bechanged. In one embodiment, a site appliance may provide informationindicating that synchronization of the configuration on that applianceshould be skipped.

The configurator of the master node, such as via the interface mayautomatically login to each slave node and use one or more remote calls,such as SSH, SFTP and/or SCP to retrieve the configuration from theslave node. Likewise, the configurator of the master node mayautomatically login to each slave node and via one or more remote calls,such as SSH, SFTP and/or SCP apply an updated configuration to eachslave node. The configurator may determine a list of appliances or sitesto retrieve a configuration via the site hierarchy configuration 420.For example, the configurator 420 may access and/or read from memory orstorage the current site hierarchy configuration of the master node. Inanother embodiment, the configurator may execute a command to output thelocally running site configuration 410. The configuration may capturethis output. The configurator may order the list of slave nodes forobtaining the configuration in any order. In some embodiments, theconfigurator may enumerate the list of slave nodes by Site identifierand/or IP address. In another embodiment, the configurator may enumeratethe list of slave nodes in accordance with the topology of the site,such as top peer nodes first, then child nodes of these top nodes next,and so on.

With an enumerated list of slave nodes, the configurator, such as viathe interface, may login to each slave node and retrieve the currentconfiguration. The configurator may obtain the userid and password orauthentication credentials for a slave in the list. Each slave node mayhave the same or different credentials. Using the credentials, theconfigurator ma login to the appliance of the slave node. Theconfigurator may execute a command on the slave node to output orprovide the current running configuration of the appliance. Theconfiguration may transfer or copy the slave node's configuration to themaster node. For example, the configurator may execute a remote shell tooutput the GSLB site configuration of a remote node to a file and remotecopy or file transfer the file to the master node.

The configurator may comprise any type and form of comparator 510 forcomparing one configuration to another configuration. The comparator maycomprise any of the software and/or hardware embodiments of theconfigurator described in conjunction with FIG. 4B. The comparator maycomprise logic, functions or operations to perform a difference betweeneach of the configuration commands of one configuration 420A to theconfiguration commands of a second configuration 420B. For example, thecomparator may perform a command by command comparison. In someembodiments, the comparator identifies the configuration commands for asite in one configuration and compares the similarities and differencesof the configurations commands for that site in a second configuration.The comparator may perform this comparison for each of the sites in theenumerated list of sites. In some embodiments, the comparator determinesthe site topology of each of the configurations being compared andoutputs differences between the site topologies. In some embodiments,the comparator determines the site topology represented by eachconfiguration and outputs those portions of the topology that are thesame. In these embodiments, the comparator may compare the topologies ofeach configuration, such as via traversing any type and form of treerepresentation, such as a linked list or data structure in memory. Thecomparator 510 may output the results of the comparison in any form orformat. In some embodiments, the comparator produces a file of thedifferences and/or similarities. In another embodiment, the comparatorprovides a data structure or an object comprising information of thedifferences and/or similarities. In some embodiments, the comparatorprovides the differences or similarities in the form of a siteconfiguration 420.

The configurator 420 may comprise a generator 515 that generates,produces or provides a configuration command set 520A-520N to addressany differences in configuration between compared configurations. Thegenerator may comprise any of the software and/or hardware embodimentsof the configurator described in conjunction with FIG. 4B. The generator515 may operate responsively to the comparator 510 and/or any outputproduced by the comparator. In some embodiments, the generator operatesresponsively to any portion of the configurator 410, such as theinterface 425 or a CLI or GUI.

The generator 515 may generate any commands or instructions 520A-520Nthat changes one configuration to match or synchronize with anotherconfiguration. For example, the generator may generate a set ofconfiguration commands to change the configuration of a slave node tomatch or synchronize with the configuration of a master node. Thegenerator may generate the configuration synchronization command set520A-520N using the same command language, syntax or format for the sitehierarchy configuration 420. The generator may generates commands,scripts or instructions as supported by the appliance. The command sets520A-N may be any type and form of script, for example a script that maybe executed via a CLI.

The commands sets 520 may include any commands, instructions orconfiguration to add sites, remove sites and/or change the configurationof a site or topology of the multi-site hierarchy. The command sets 520may include any commands or instructions to change one or moreparameters or options of a site configuration. The commands sets 520 mayinclude any instructions to halt operations while making the changes.The commands sets 520 may include any instructions to backup or savecopies of the current configuration. The commands sets 520 may includeany instructions to set a rollback point of the configuration. In someembodiments, the commands set 520 are designed and generated such thatthe result of running the command set is a currently runningconfiguration of a slave node matching or corresponding to the currentlyrunning configuration of a master node. In some embodiments, thecommands set 520 are designed and generated such that the result ofrunning the command set is a currently running GSLB site hierarchyconfiguration of a slave node matching or corresponding to the currentlyrunning GSLB site hierarchy configuration of a master node.

Each of the command sets may be the same or different. In someembodiments, each of the retrieved configurations of the slave nodes aredifferent resulting in different command sets to synchronize each of theslave. In other embodiments, each of the retrieved configurations of theslave nodes are the same resulting in the same command sets tosynchronize each of the slave. In another embodiment, some of theretrieved configurations of the slave nodes are the same and others aredifferent resulting in some generated command sets being the same andother generated command sets being different.

The configurator via the interface 425 may apply the configurationcommands sets to each slave appliance to synchronize the configurations.In some embodiments, the configurator synchronizes configurationsresponsive to the generator and/or comparator. In other embodiments, theconfigurator synchronizes configurations on a predetermined schedule. Insome embodiments, the configurator synchronizes configurations based ona request from a slave node. In another embodiment, the configuratorsynchronizes configurations based on user input or responsive to arequest of a user.

Referring now to FIG. 5B, an embodiment of steps of a method forsynchronizing configurations between appliances is depicted. In briefoverview, at step 580, a master node is identified and the master nodelogs in to slave nodes. At step 582, the master node obtains theconfiguration from these appliances. At step 584, the master nodecompares each of the obtained configurations to the configuration of themaster node. At step 586, the master node generates a configurationcommand set for each appliance based on the comparison. at step 588, themaster node applies each of the configuration commands to thecorresponding appliances to synchronize configuration. At step 590, eachof the appliances operate with the synchronized configuration.

In further details, at step 580, a user, such as an administrator, mayidentify any appliance of any site as a master node for configuring thesite hierarchy. In some embodiments, the user identifies a top node as amaster node. In another embodiment, the user identifies an appliancethat is a child of a parent site as the master node. In someembodiments, the user identifies a plurality of appliances as masternodes. In some cases, an appliance is designated as a backup masternode. In some embodiments, the user specifies via configuration of theappliance that the appliance is a master. In another embodiment, anappliance is considered a master node because the user configures thesite hierarchy on that appliance.

The master node may be configured with or operating any type of GSLBsite hierarchy. The site hierarchy of the master node may define orspecify any topology with any combination of one or more peer sites,parent sites and/or child sites. In some embodiments, the user defines asite hierarchy with a single top node. In other embodiments, the userdefines a site hierarchy with multiple peers nodes at the top of thehierarchy. The user may specify in the site hierarchy any number oflevels of parent and child nodes. Each peer node may be a parent to anynumber of sites. Each site that is a child of a top node may also beparent node having any number of children and each child may further bea parent to any number of further children nodes.

At step 582, the master node may obtain site hierarchy configurationfrom one or more other appliances or slave nodes in the multi-sitedeployed represented by the master node's site hierarchy. In someembodiments, upon request of a user, the master node identifies theappliances and sites in the master's nodes site hierarchy. The masternode may automatically login to each appliance using any predeterminedauthentication scheme. The master node may execute any shell or commandline commands to obtain a site hierarchy configuration of each of slavenodes and transfer or copy the configuration to the master node. In someembodiments, the master node obtains these configurations concurrently.In other embodiments, the master node obtains these configurationssubsequently. The master node may uniquely identify and store eachconfiguration from each slave node in memory or storage. In someembodiments, the master node determines that one or more slave nodesshould not be synchronized. For example, configuration on the masternode or slave node may identify that a configuration of a slave nodeshould not be changed or the slave node is not participating insynchronization. Responsive to this identification, any one or moresteps of this method may be skipped or not performed.

At step 584, the master node such as via the comparator compares each ofthe obtained slave node configurations with the master's nodeconfiguration. In some embodiments, the master node performs thiscomparison upon receipt of the slave node's configuration. In otherembodiments, the master node performs this comparison upon receipt ofconfigurations from all identified slave nodes. In one embodiment, themaster node performs the comparison with batches of a plurality of slavenode configurations. In some embodiments, the master node determines ifany of the slave node's configuration are the same and responsive to thedetermination performs a comparison once for the common configuration.

At step 586, the master node generates a configuration command set foreach slave node configuration to synchronize the slave nodesconfiguration with the master nodes configuration. In some embodiments,the generator of the master node generates a configuration command setresponsive to comparison by the comparator. In other embodiments, thegenerator of the master node generates a configuration command set foreach slave node responsive to a user or user request.

At step 588, the master node applies the commands sets to synchronizeconfiguration at each corresponding slave node. In some embodiments, theinterface of master node applies the synchronization command setsresponsive to the generator. In some embodiments, the interface of themaster node applies the synchronization commands set upon generation. Inother embodiments, the interface of the master node applies thesynchronization command sets upon completion of comparison and/orgeneration of all identified slave nodes configuration. In someembodiments, the master node applies the synchronization command setsconcurrently with each other. In other embodiments, the master nodeapplies the synchronization command sets subsequently to each other. Insome embodiments, the master node applies synchronization command setsin accordance with levels of the hierarchy starting from either the topnode or a bottom leaf node.

At step 590, as a result of completing the synchronization ofconfigurations among the appliances in a multi-site deployment, each ofthe appliances operates with at least a same portion of the sitehierarchy of the master node. In some embodiments, each of theappliances operate with the same GSLB site hierarchy. In otherembodiments, some of the appliances operates with the same GSLB sitehierarchy while some other appliances operate with a portion of the sameGSLB site hierarchy. Responsive to the updates or changes to the GSLBsite hierarchy, any one appliance may changes the appliance's operationin view of the update or change. In some embodiments, one or moreappliances may disestablish or drop a metric exchange connection. Inanother embodiment, one or more appliances may establish a metricexchange connection.

Although the embodiment of the method of FIG. 5B may at times bedescribed in connection with a GSLB site hierarchy 420, the systems andmethods described herein may be used for any type and form ofconfiguration that may be common, shared or batchable across appliances.

Although the embodiment of the method of FIG. 5B is described in view ofthe master node obtaining configurations, performing comparison andgenerating configuration changes, each of the slave nodes may obtain themaster nodes configuration, perform the comparison and generate andapply the configuration changes on the slave node.

What is claimed:
 1. A method for synchronizing configurations between aplurality of global server load balancing (GSLB) appliances, the methodcomprising: a) identifying, by a user, a first appliance as a masterGSLB node, the first appliance and one or more appliances identified toprovide GSLB services; b) obtaining, by the first appliance from each ofthe one or more appliances via a login by the first appliance to each ofthe one or more appliances, a GSLB configuration currently executing oneach of the one or more appliances; c) comparing, by the first applianceupon receipt, the GSLB configuration currently executing on each of theone or more appliances to a first GSLB configuration executing on thefirst appliance, the first GSLB configuration comprising a change to atopology of a multi-site hierarchy comprising the one or more appliancesproviding GSLB services; d) generating, by the first applianceresponsive to the comparison, a configuration command set for each ofthe one or more appliances based on the comparison, each of theconfiguration command sets comprising one or more commands tosynchronize the GSLB configuration with the first GSLB configuration ofthe appliance; and e) applying, by the first appliance responsive to thegenerating and via the login by the first appliance to each of the oneor more appliances, each of the configuration command sets to thecurrently executing GSLB configuration of a corresponding appliance ofthe one or more appliances to synchronize the currently executing GSLBconfiguration of the corresponding appliance to the currently executingfirst GSLB configuration of the first appliance; f) establishing ordisestablishing, by the one or more appliances responsive tosynchronization to the currently executing first GSLB configuration ofthe first appliance, a metric exchange connections with at least oneappliance at a different level of the plurality of levels of themulti-site hierarchy based on the changes to the topology of themulti-site hierarchy, the one or more appliances are configured toidentify parent-child relationships in the multi-site hierarchy and toestablish metric exchange connections to each appliance in themulti-site hierarchy based on the parent-child relationships to exchangeload balancing statistics via transport layer connections; and g)exchanging, by the one or more appliances, load balancing statisticswith the at least one appliance at the different level of the pluralityof levels of the multi-site hierarchy based on the topology of themulti-site hierarchy.
 2. The method of claim 1, wherein step (a) furthercomprises configuring the first appliance to auto-login to each of theone or more appliances.
 3. The method of claim 1, wherein step (b)further comprises determining, by the first appliance, the one or moreappliances identified by the first GSLB configuration.
 4. The method ofclaim 1, wherein step (b) further comprises automatically performing, bythe first appliance, a login to each of the one or more appliances. 5.The method of claim 1, wherein step (b) further comprises executing, bythe first appliance, a command on each of the one or more appliances tooutput a currently executing GSLB configuration.
 6. The method of claim1, wherein step (c) further comprises determining, by the firstappliance, one or more differences between the first GSLB configurationand the GSLB configuration of each of the one or more appliances.
 7. Themethod of claim 1, wherein step (d) further comprises generating, by thefirst appliance based on the comparison, a first configuration commandset for synchronizing a currently executing GSLB configuration of asecond appliance with the first GSLB configuration and a secondconfiguration set for synchronizing a currently executing GSLBconfiguration of a third appliance with the first GSLB configuration. 8.The method of claim 1, wherein step (e) further comprises executing, bythe first appliance, on each of the one or more appliances a remotecommand to apply the GSLB configuration set corresponding to each of theone or more appliances.
 9. The method of claim 1, wherein step (e)further comprises executing, by each of the one or more appliancesresponsive to applying the configuration command set, a GSLBconfiguration corresponding to the first GSLB configuration.
 10. Asystem for synchronizing configurations between a plurality of globalserver load balancing (GSLB) appliances, the system comprising: a firstappliance identified as a master GSLB node, the first appliance and oneor more appliances identified to provide GSLB services; an interface ofthe first appliance obtaining from each of the one or more appliancesvia a login by the first appliance to each of the one or moreappliances, a GSLB configuration currently executing on each of the oneor more appliances; a comparator of the first appliance comparing, uponreceipt, the GSLB configuration currently executing on of the one ormore appliances to a first GSLB configuration executing on the firstappliance, the first GSLB configuration comprising a change to atopology of a multi-site hierarchy comprising the one or more appliancesproviding GSLB services; a generator of the first appliance generating,responsive to the comparison, a configuration command set for each ofthe one or more appliances based on the comparison, each of theconfiguration command sets comprising one or more commands tosynchronize the GSLB configuration with the first GSLB configuration ofthe appliance; and wherein the first appliance applies, responsive tothe generating and via the login by the first appliance to each of theone or more appliance, each of the configuration command sets to thecurrently executing GSLB configuration of a corresponding appliance ofthe one or more appliances to synchronize the currently executing GSLBconfiguration of the corresponding appliance to the currently executingfirst GSLB configuration of the first appliance; wherein the one or moreappliances, responsive to synchronization to the currently executingfirst GSLB configuration of the first appliance, establishes ordisestablished a metric exchange connection with at least one applianceat a different level of the plurality of levels of the multi-sitehierarchy based on the changes to the topology of the multi-sitehierarchy, the one or more appliances are configured to identifyparent-child relationships in the multi-site hierarchy and exchangesload balancing statistics with the at least one appliance at thedifferent level of the plurality of levels of the multi-site hierarchybased on the topology of the multi-site hierarchy.
 11. The system ofclaim 10, wherein the first appliance is configured to auto-login toeach of the one or more appliances.
 12. The system of claim 10, whereinthe first appliance determines the one or more appliances identified bythe first GSLB configuration.
 13. The system of claim 10, wherein theinterface automatically performs a login to each of the one or moreappliances.
 14. The system of claim 10, wherein the interface executes acommand on each of the one or more appliances to output a currentlyexecuting GSLB configuration.
 15. The system of claim 10, wherein thegenerator based on the comparison generates a first configurationcommand set for synchronizing a currently executing GSLB configurationof a second appliance with the first GSLB configuration and a secondconfiguration set for synchronizing a currently executing GSLBconfiguration of a third appliance with the first GSLB configuration.16. The system of claim 10, wherein the interface executes on each ofthe one or more appliances a remote command to apply the configurationcommand set corresponding to each of the one or more appliances.
 17. Thesystem of claim 10, wherein each of the one or more appliances executes,responsive to applying the configuration command set, a GSLBconfiguration corresponding to the first GSLB configuration.
 18. Themethod of claim 1, wherein the one or more appliances are configured toidentify appliances at the same level in the multi-site hierarchy as theone or more appliances and to establish metric exchange connections tothe applications at the same level in the multi-site hierarchy toexchange load balancing statistics via transport layer connections. 19.The method of claim 1, wherein the one or more appliances are configuredto identify appliances at a different level in the multi-site hierarchyas the one or more appliances and to establish metric exchangeconnections to the applications at the different level in the multi-sitehierarchy to exchange load balancing statistics via transport layerconnections.
 20. A method for synchronizing configurations between aplurality of global server load balancing (GSLB) appliances, the methodcomprising: a) identifying a first appliance as a master GSLB node, thefirst appliance and one or more appliances identified to provide GSLBservices; b) obtaining, by the first appliance from each of the one ormore appliances via a login by the first appliance to each of the one ormore appliances, a GSLB configuration currently executing on each of theone or more appliances; c) comparing, by the first appliance uponreceipt, the GSLB configuration currently executing on each of the oneor more appliances to a first GSLB configuration executing on the firstappliance, the first GSLB configuration comprising a change to atopology of a multi-site hierarchy comprising the one or more appliancesproviding GSLB services; d) generating, by the first applianceresponsive to the comparison, a configuration command set for each ofthe one or more appliances based on the comparison, each of theconfiguration command sets comprising one or more commands tosynchronize the GSLB configuration with the first GSLB configuration ofthe appliance, wherein the configuration command set generated for eachof the one or more appliances is unique for each of the one or moreappliances; and e) applying, by the first appliance responsive to thegenerating and via the login by the first appliance to each of the oneor more appliances, each of the configuration command sets to thecurrently executing GSLB configuration of a corresponding appliance ofthe one or more appliances to synchronize the currently executing GSLBconfiguration of the corresponding appliance to the currently executingfirst GSLB configuration of the first appliance; f) establishing ordisestablishing, by the one or more appliances responsive tosynchronization to the currently executing first GSLB configuration ofthe first appliance, a metric exchange connections with at least oneappliance at a different level of the plurality of levels of themulti-site hierarchy based on the changes to the topology of themulti-site hierarchy, the one or more appliances are configured toidentify parent-child relationships in the multi-site hierarchy and toestablish metric exchange connections to each appliance in themulti-site hierarchy based on the parent-child relationships to exchangeload balancing statistics via transport layer connections; and g)exchanging, by the one or more appliances, load balancing statisticswith the at least one appliance at the different level of the pluralityof levels of the multi-site hierarchy based on the topology of themulti-site hierarchy.